Fox News contributor Bill Kristol has recently headed a relentless attack campaign against former Sen. Chuck Hagel after President Obama nominated Hagel to be the next defense secretary. However, Kristol used to speak favorably towards Hagel, only changing his opinion when Hagel voted in favor of a withdrawal timeline for the Iraq War in 2007.

Kristol's opposition to Hagel was on full display today when he took to Fox's America's Newsroom to smear the nominee as anti-Israel. 

However, as Think Progress noted, back in 2000, Kristol spoke in favor of Hagel, at one point describing him as an “impressive and attractive first-term senator” with a “decent shot” at becoming the VP for George W. Bush.

What changed? As The New York Times reported on March 28, 2007, Hagel shocked both Republicans and Democrats by voting in favor of a military spending bill that included a withdrawal date for troops in Iraq -- something Republicans were emphatically against. From the Times:

By a vote of 50 to 48, with a few crucial votes shifting in favor of the Democratic position, the Senate rejected a Republican effort to strip from the military spending bill any mention of a withdrawal date. The legislation will now move forward with a provision to begin a gradual withdrawal of American troops from Iraq within 120 days of the measure's enactment, with a nonbinding goal of pulling out by March 31, 2008.

[...]

The outcome of the Senate vote took both parties by surprise. Republicans were stung by the defection of Senator Chuck Hagel of Nebraska, who has not supported a timetable for withdrawal before although he is his party's most outspoken critic of the war in Congress.

“There will not be a military solution to Iraq,” Mr. Hagel declared. “Iraq belongs to the 25 million Iraqis who live there. It doesn't belong to the United States. Iraq is not a prize to be won or lost.”

Watch as Kristol turned on the former Senator he once called “impressive and attractive,” instead describing him as “irresponsible,” during the March 27, 2007, edition of Fox News' Special Report with Brit Hume: