Story highlights Hillary Clinton's presidential campaign is challenging Bernie Sanders' consistency on a host of issues in the run up to the Iowa caucuses

She's hitting her Democratic rival in an area that many of his die-hard supporters feel differentiates the two candidates

Des Moines, Iowa (CNN) Hillary Clinton's presidential campaign is challenging Bernie Sanders' consistency on a host of issues in the run up to the Iowa caucuses, hitting her Democratic rival in an area that many of his die-hard supporters feel differentiates the two candidates.

And so far, the effort is getting results.

Clinton's campaign, in the last week, has compelled Sanders to disavow a 2005 gun vote break a pledge not to raise taxes on the middle class in his healthcare proposal and backtrack on his call for Iranian troops on the ground in Syria.

The latest skirmish in this effort -- the Clinton campaign's attempt to cast the Vermont senator as a foreign policy lightweight regarding Iran and Syria -- reached a pinnacle on Thursday when Sanders told The New York Times that he never called for Iranian troops on the ground in the war-torn country.

"No," Sanders said when asked whether he called for Iranian troops in Syria. "What I have said is that I would like to see -- and I understand, believe me, that Iran and Saudi Arabia hate each other -- but, to the degree that we can, create a process where Muslim countries can come together to fight ISIS."

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