Updated, Aug. 6 | Diverging views on free speech and protests took center stage Tuesday at the Senate Judiciary Subcommittee on the Constitution’s hearing on free speech, protest and anarchist violence.

Witnesses included Kyle Shideler, a senior analyst for the Center for Security Policy, a think tank that has come under fire for its founder’s views on Muslims.

“I would like to record my concern regarding the presence of the Center for Security Policy at this hearing. The Center for Security Policy, the CSP, is an organization that has been spreading anti-Muslim conspiracy theories,” said Sen. Mazie K. Hirono, D-Hawaii.

Hirono continued, “CSP has been criticized by Republicans and Democrats alike, and organizations that monitor extremist groups, including the Anti-Defamation League … and the Southern Poverty Law Center has designated CSP as a hate group.”

Shideler sought to defend the center: “We reject this claim from organizations that are engaging in behavior which is essentially the same that antifa engages in, which is to say that anyone that offers an analysis that disagrees with them must ipso facto be a member of an unacceptable organization or a hate group or what have you.”

Another witness on the panel was Andrew Ngo, a Portland-Ore.-based editor-at-large of the conservative Canadian news site The Post Millennial. He was introduced as an independent journalist by subcommittee Chairman Ted Cruz, R-Texas.

Ngo has written controversial articles about Islam, including a Wall Street Journal op-ed that was corrected for falsely suggesting that “alcohol-free zones” in England were connected to the immigrant Muslim population.

Watch video of the hearing above. Video of the full multi-paneled hearing is also available on the Senate Judiciary Committee’s website.

Update: This report was revised to include testimony from other witnesses and Kyle Shideler’s response to Sen. Hirono. Watch Shideler’s entire statement.