At the Conservative Political Action Conference last week, Wisconsin Gov. Scott Walker drew a comparison between ISIL terrorists and the Wisconsin union protesters with whom he has repeatedly clashed since 2011.

In response to a question about how he would deal with such global threats such as the one posed by the Islamic State in Iraq and the Levant, Walker drew from personal ­experience.

"If I can take on 100,000 protesters, I can do the same across the world," Walker said on the CPAC stage, after giving a longer answer about how he would handle ISIL if he were the president.

He walked back the comments in a subsequent appearance on "With All Due Respect" on Thursday, saying, "My point was just, if I could handle that kind of a pressure and kind of intensity, I think I'm up for the challenge for whatever might come, if I choose to run for president."

Union criticism

Still, following the speech and its clarification, Walker has faced bipartisan criticism. Sen. Elizabeth Warren, D-Mass., an outspoken labor supporter, bashed Walker on Twitter. "If Scott Walker sees 100,000 teachers & firefighters as his enemies, maybe it's time we take a closer look at his friends."

Predictably, the Walker comments also did not sit will with labor leaders. Richard Trumka, president of the American Federation of Labor and Congress of Industrial Organizations, took to Twitter to call on Walker to disavow the parallel he had seemingly drawn. Trumka also issued this statement: "Governor Walker's statement comparing workers and terrorists is revolting. It is clear that Governor Walker's judgment is impaired, and that he is not qualified for the Presidency. I call on Governor Walker to personally and immediately retract his statement, and apologize …"

Former Texas Gov. Rick Perry, a possible 2016 rival, at first criticized the comparison, saying on MSNBC that "you are talking about, in the case of ISIS, people who are beheading individuals and committing heinous crimes, who are the face of evil. To try to make the relationship between them and the unions is inappropriate."

On Sunday, Perry said on CNN's "State of the Union" that Walker's clarification was sufficient. "I think the initial response when I heard that was, 'That's not right. You don't make that connection,' " Perry said. "The governor's gone back and clarified his remarks since then, and clearly said that's not what he was talking about …"

Appearing on "Face the Nation" on Sunday, former Arkansas Gov. Mike Huckabee, another potential 2016 contender, declined to address the issue.

Walker is not the first Republican to compare — or seem like he was comparing — Americans to ISIL. In January, Dr. Ben Carson compared the soldiers of the American Revolution to the militants.

On Sunday, Walker moved on to another hot button issue: immigration.

Walker said he once envisioned a world where the 11 million immigrants living in the country illegally could embark on a path to citizenship. But now he calls that position "amnesty" and says his view has changed.

"I don't believe in amnesty," Walker told "Fox News Sunday." ''My view has changed. I'm flat out saying it. Candidates can say that."

The Associated Press contributed to this report.