Siddique has a long record of statements rationalizing and defending terrorist actions and has written repeatedly about the Islamic prohibition against insulting the faith, including images of Islam's prophet Muhammad.
"Almost all Islamic scholars agree that one who insults, abuses or ridicules the Prophet, pbuh (peace be upon him), should be killed," Siddique wrote after January's massacre at the offices of French satirical magazine Charlie Hebdo killed 12 people.
He also claimed that "Abuse of the Prophet, pbuh, is a form of cultural genocide" and described making cartoons of Muhammad as "acts of war against Islam." Siddique further stated that "[a]cts of war are always countered by those Muslims who have the ability and will do it."
The Muslim world would never "accept the abuse of the Prophet, pbuh, in the name of freedom of expression," Siddique wrote.
Lincoln University has disassociated itself from Siddique's inflammatory rhetoric – he also has questioned the Holocaust and made anti-gay statements – but says the "bedrock principle" of academic freedom limits further action against the tenured English professor.
In his letter, Williams challenged the university's position.
"Academic freedom is certainly important, but so is academic integrity," Williams wrote. "Allowing a member of your faculty to continue spreading hateful, vile lies in the public arena is irresponsible; to protect him from any form of discipline for such actions is unconscionable."
In an interview, Williams told the Investigative Project on Terrorism (IPT) that Siddique's defense of terrorists violates the requirements for him to keep his tenure and warned they threaten Lincoln University's integrity and that of its students.
"Free speech does not mean that you can walk into a crowded theater and cry fire," Williams said. "Dr. Siddique has crossed that line several times."
The most recent example involved Siddique's claim to The Philadelphia Inquirer that free-speech advocate Pamela Geller's "Draw Muhammad" contest was tantamount to killing Muslims. Geller told the IPT that she felt Siddique's comment equaled incitement for Muslims to kill her.
Williams previously expressed concern over Siddique's anti-Semitic rhetoric and Holocaust denial. In 2010, he and State Sen. Daylin Leach wrote to then-Lincoln University President Ivory Nelson, inquiring whether Siddique's sentiments were reflected in his classroom teaching. Leach described Siddique's comments as "blatant hate speech." Lincoln kept Siddique on its payroll despite that controversy citing academic freedom.
A university spokesman declined to comment when contacted by the IPT, but pointed to a statement on its website.
"At Lincoln University, we acknowledge Dr. Siddique's right to free speech," the statement said. "Academic freedom is a bedrock principle for institutions of higher education. However, the university does recognize why many have reacted negatively to his comments. Lincoln University does not condone bigotry in any form and does not hold the opinions of Dr. Siddique. We are committed to providing a learning environment that is inclusive and welcoming to all."
Williams is scheduled to meet with Lincoln University President Richard Green later this week.
Siddique told the Inquirer he had no regrets for directing a prior anti-Semitic diatribe at Geller, calling her and others who share her beliefs "dirty Jewish Zionist White Supremacists thugs" in a May 30 Facebook post.
Siddique rebutted Williams' accusations against him on Facebook on Wednesday, saying that the senator did not know anything about him or his relationship with his students. He made no effort to confront the facts contained in Williams' letter and deflected his criticism.
"The Senator thinks I should be dismissed because I stand against his views and those of the supporters of Israel. I would remind him that this is not Israel. I am a citizen of the United States and we still have First Amendment rights," Siddique wrote. "Our students are struggling against the situation in American cities. We have police brutality in many cities. I stand with my students in all these issues."
Siddique Accuses Pamela Geller of All But Killing Muslims
Siddique's views about the Charlie Hebdo attack raise questions about what he meant in his Philadelphia Inquirer interview. He claimed that Geller's "Draw Muhammad" contest in May amounted to "cultural genocide" and that that it was tantamount to killing Muslims.
"She did the worst, other than killing us," Siddique told the Inquirer.
Two gunmen agreed and tried to storm the cartoon contest and kill Geller and as many people inside as possible. They were shot dead by law enforcement officers before they were able to get inside the building.
To Geller, already the subject of death threats from the Islamic State (ISIS) and others, Siddique's comments that she had done "the worst, other than killing us" had a clear meaning.
"This is certainly incitement," Geller told the IPT in an email. "Kaukab Siddique must know that [the ISIS threat] exists. And he is telling Muslims that what I have done in standing for free speech is tantamount to genocide. He is in effect pleading with jihadis to kill me. And this is just fine with the American academic establishment today."
In Facebook comments on May 4, Siddique described the Muhammad cartoon contest as an "act of war on Islam" and a form of "blasphemy."
"Saying that insulting the prophet, pbuh (peace be upon him), is freedom of speech is kufr (blasphemous)," Siddique wrote. "Try insulting the Jews."
A 2006 Canadian intelligence report found that perception that Islam is under attack from the West is the single most important factor in radicalizing Muslims.
To Siddique, the notion of a western war on Islam is not a point of view, but a fact. Cartoons depicting the prophet are weapons in that war, which is why al-Qaida and others urge jihadists to attack. "This is what the West needs to understand," he wrote in January. "The Muslim world will NEVER accept abuse of the Prophet, pbuh, in the name of freedom of expression."
Taken collectively, Siddique's seeming endorsement of attacks on people who caricature Muhammad, in the eyes of an ISIS sympathizer, reinforces the terror group's narrative that Islam is under attack and its repeated calls to kill any enemy of Islam. ISIS laid out a penal code in its manual for lone jihadis called "How to Survive In the West."
"Allah is asking us; why don't you fight a people who broke their covenant of peace (with the Muslims) first, then reviled our religion (by promoting insulting pictures of Prophet Muhammad) and started (Arabic: bada'*) the attack against you first?" a passage in the manual said.
Siddique likely would deny having violent intent against Geller; he has said that Muslims should be "non-violent" when denouncing Muhammad cartoons. But he never condemned the failed May 3 terror attack in Garland, Texas.
But his comment that Geller "did the worst, other than killing us" in organizing the Garland contest could encourage an ISIS sympathizer to kill her, said Ahmed Subhy Mansour, a Muslim scholar opposed to jihadism.
"I think what she said has nothing to do with the Muslim life here in the entire West," Mansour said. "But what he says about her may endanger her life."
Siddique seemed to endorse the attempted Garland attack, writing: "Very cleverly, the corporate media are trying to present the Texas situation as ISIS vs. Geller. The Prophet Muhammmad, pbuh, is the, (sic) leader of the ENTIRE UMMAH (community), not just of ISIS. Two of ISIS gave their lives for the honor of the Prophet, pbuh."
When Siddique writes about ISIS, he expresses doubts about the horrors it has committed, even when ISIS has boasted about those very acts.
In a May 9 post, he denied that ISIS had killed children. He also attacked Fox News while dredging up the anti-Semitic conspiracy theory that Jews control the American news media. "Fox wasn't satisfied and brought on a nutty book author who claimed that ISIS has been killing children. Zionist control of the media is so strong that FOX can say ANYTHING against the mujahideen and no one will challenge it."
Mujahideen are Muslim fighters engaged in jihad, but rivals reject the Islamic State's use of the term. For example, Al-Qaida cleric Abu Qatada says ISIS fighters are more akin to members of a "mafia" than to mujahideen.
Siddique's defense of the Islamic State sets him apart from other American Islamists who insist that the terror group has nothing to do with Islam.
"Notice how he doesn't condemn ISIS," Geller said. "He says that ISIS is part of the umma, in arguing that the entire umma should be trying to kill me, not just ISIS. Siddique is, like ISIS, trying to enforce sharia blasphemy laws by force, trying to intimidate the West into silence in the face of the jihad threat."
Siddique's apologism for those responsible for the Charlie Hebdo attack and the terrorists who hoped to kill Geller and others in Garland is part of a pattern. Back in 2004, he said that Muslims could not wage violent jihad in non-Muslim majority countries. However, that did not keep him from defending Major Nidal Hasan after the Fort Hood massacre five years later, saying: "If it turns out that he was fighting for Islam and striking back at military forces bent on occupying Muslim lands, he should be considered a mujahid (Islamic holy warrior), and if he dies, a shaheed (martyr)."
Siddique Cheerleads For ISIS
Other recent writings suggest Siddique sympathizes with ISIS.
As editor-in-chief of NewTrendMag.org, the online publication of his organization Jamaat al-Muslimeen, Siddique often writes about news of the day.
While the organization's size is unclear, Jamaat al-Muslimeen "contributes to a permissive environment for violent radicalization by validating core assumptions shared by nearly all homegrown Islamist terrorists," a 2011 report by West Point's Combating Terrorism Center (CTC) said. Although it explicitly disavows engaging in violent jihad in the U.S., the CTC report notes that Jamaat Al-Muslimeen has no problem defending terrorist acts abroad and describes American Muslims convicted of terrorism as victims of government persecution.
"In America, Muslims have the duty of peacefully giving the message of Islam. The jihad with the sword is not applicable to a Muslim minority living in a non-Muslim country. Jihad with weapons is appropriate where Muslims are being physically attacked," Siddique wrote in NewTrend in April 2004.
Accusations of ISIS human-rights violations were part of a smear campaign, Siddique claimed in a February editorial. In an October sermon, he called evidence against the Islamic State was a "bunch of lies. There is no evidence against ISIS. Anyone who tries to set up an Islamic caliphate will be treated the same way."
When Saudi Arabia's grand mufti called ISIS "the enemy number one of Islam," Siddique fired back, calling it "a shame ... to attack the Islamic State [IS] in particular and all those whom America sees as enemies."
Furthermore, Siddique praised the ISIS caliphate last September because it "abolished the imperialist borders between Syria and Iraq."
In a sermon published a week later, Siddique dismissed Western reports about ISIS atrocities.
"Muslims should note the daily attacks on the Caliphate (ISIS) in [t]he media. Do not be fooled. These are attacks on Islam," Siddique said. "Do not be fooled by the media hype against IS. Whenever Muslims set up the Caliphate, it will be attacked by the Western powers." Siddique expressed skepticism that ISIS raped Yazidi women in a July 25 rebuttal to a Daily Beast article about his extremist rhetoric, calling the accusation baseless: "The mainstream media tell us that ISIS is enslaving women for sex, in particular Yazeedi women. I told [the Daily] Beast that women are rushing to JOIN ISIS, not to leave it, and many of these are 'liberated' women from western countries. If ISIS is enslaving women, why are western women rushing to join ISIS, even defying laws against joining it?"
Siddique also sympathizes with Hamas, writing in July 2014: "Dear sisters and brothers, today Hamas fought very well against the zionist monster. Israel admitted that 13 of its best troops were killed today. One military Jew was captured. Civilian casualties of palestinians were extremely heavy because the rabid dogs of the Jews were doing their worst."
In 2005, Siddique condemned major American Islamist groups, calling them "Government Lackeys" for issuing a fatwa against terrorism because he argued that American Muslims had done nothing related to terrorism.
Siddique's History of Anti-Semitism
In Siddique's view, "bigots and fabricators" in the media are the problem, not his anti-Semitism or terrorist apologia. He repeated his attack against those he called "Zionist Jews," pointing to Geller and to Spencer, an Eastern Catholic deacon. Siddique also accused IPT Executive Director Steven Emerson of falsely accusing him of being a Holocaust denier.
His Facebook page frequently uses anti-Semitic terms to describe prominent Jews. He referred to Harvard Law professor Alan Dershowitz as a "Zionist Jewish dog" in July and CNN anchor Wolf Blitzer as a "dirty Zionist Jew" in May.
Siddique's anti-Semitic and anti-Israel sentiments landed him in hot water in 2010 after he called for Israel's destruction.
"The time has come that we must stir up our 'religious leaders' in this country to speak the truth about Israel," Siddique said at a September 2010 rally in Washington. "They must put their hands on the Quran and say that they do not recognize Israel as a legitimate entity. If they cannot do that, they must be branded as kaffirs (infidels). It's as simple as that. Because the Quran says – drive them out from where they drove you out."
This incident brought Siddique's prior work under scrutiny – particularly his statements about the Holocaust. He claimed in a 2009 article which carried the headline, "What's Wrong with the Jewish Auschwitz and Holocaust Story?"
"The Jews claimed that they had suffered more than anyone else and their suffering was the product of a mindset to be called anti-semitism. To make this horror come alive, the story of the GASSING of the JEWS in Auschwitz and other concentration camps was invented. This story is so horrible that once it's accepted, it puts the Jews as victims above ALL OTHERS for EVER."
Lincoln University is correct in asserting that academic freedom is a treasured value in higher education. His anti-Semitism and praise for Hamas may be distasteful, yet are within the bounds of academic freedom.
But incitement to violence, whether blatant or subtle, should be considered anathema to those same values. Recent history shows that it doesn't take much for a radical Islamist to seek vengeance in Mohammad's name against those who dared draw a caricature of his image.
Williams' concern, therefore, is well founded. What will Lincoln University do about it?