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"Let no one be mistaken Donald Trump’s candidacy is a cancer on conservatism and it must be clearly diagnosed, excised, and discarded," Perry said during a speech in Washington, D.C. "It cannot be pacified or ignored for it will destroy a set of principles that has lifted more people out of poverty than any force in the history of the civilized world and that is the cause of conservatism."
Perry stated Trump was "born into privilege," and "couldn't have endured for five minutes what John McCain endured for five-and-a-half years," causing the audience of roughly 50 to burst into applause.
Trump also drew fire for his remarks about Mexican immigrants last month.
"Donald Trump the candidate is a sore of division, wrongly demonizing Mexican Americans for political sport," Perry said. "It is wrong to paint with a broad brush Hispanic men and women in this country who have fought and died for freedom from the Alamo to Afghanistan."
Perry also likened Trump to the defunct "Know-Nothing" party that carried strong anti-immigrant and anti-Catholic sentiments. Perry said he, "scapegoats Hispanics to appeal to our worst instincts."
At an event hosted by the Opportunity and Freedom PAC, one of the super PACs backing his campaign, Perry, the former Texas governor, added Trump: "offers a barking carnival act that can best be described as Trumpism: a toxic mix demagoguery and mean-spiritedness and nonsense that will lead the Republican Party to perdition if pursued."
While Perry said Trump's ability to generate ratings creates a "sore of division," it won't keep him from the stage of the first Republican presidential debate scheduled for August 6 in Cleveland. A new ABC News/Washington Post poll shows Trump is leading the GOP pack, leaving Perry on the cusp of not making it to the debate. The debate will only feature the 10 most popular Republican candidates. Perry told reporters following his remarks that he isn't worried.
The former Texas governor did offer some advice to the mogul-turned-candidate, who will be making a trip to the U.S.-Mexico border Thursday.
"I hope he can find the border because I'm not sure that he's ever been there before," Perry joked. "But in all seriousness, he owes an apology to the men and women of the Texas National Guard. ...if there's one bit of advice that I would give to Mr. Trump as he goes to Texas, it is to recognize the fact that it is not the state of Texas or any state's responsibility to be securing the border."
ABC's Jill Ornitz contributed to this report.