WASHINGTON - In 2006, Rick Santorum was decisively tossed out of his Senate seat in Pennsylvania by 18 points, in a wave election where Democrats romped largely because of President George W. Bush's unpopularity.
Six years later, Santorum is running for Bush's old job, but the former president is still a weight around his neck.
Santorum was dragged down in Wednesday night's debate by his support for a few of Bush's initiatives.
The 2002 No Child Left Behind legislation was the Bush agenda item that hurt Santorum most in the debate. Santorum said his support for the measure was "a mistake."
"It was against the principles I believed in, but, you know, when you're part of the team, sometimes you take one for the team, for the leader," Santorum said.
Mitt Romney, ignoring the fact that he himself supported No Child Left Behind, made hay Thursday with Santorum's ill-advised quip.
"I wonder which team he was taking it for," Romney said at a campaign stop in Phoenix. "My team is the American people, not the insiders in Washington."
Others said it was no mystery which team Santorum was on.
"The team he was taking it for was President George W. Bush in his first year in office," said Bill Kristol, the founder of the conservative Weekly Standard, on Fox News.
But Kristol said that Santorum's admission that he had erred was to the Pennsylvanian's credit, and that Romney's 2006 health care overhaul when he was governor of Massachusetts is a bigger problem for him.
"Maybe No Child Left Behind was bad legislation. Rick Santorum said last night, 'I made a mistake.' Mitt Romney has never said about RomneyCare, 'I made a mistake.' And as a conservative, I think RomneyCare is a heck of a lot bigger mistake than the No Child Left Behind bill," Kristol said.
Romney also dinged Santorum Wednesday for two other times that Santorum helped Bush, namely his 2004 endorsement of fellow Pennsylvania Sen. Arlen Specter -- which was important to the White House at the time so that they kept control of the Senate -- and Bush's imposition of tariffs on imported steel in 2002.
Santorum's steel tariff decision was driven as much by parochial self-interest as any loyalty to Bush, but it was nonetheless a controversial decision with conservatives for Bush to put the trade barriers in place, and Santorum's support -- at a time when he was the number three Republican in the Senate -- was a help to the White House.
The way in which Bush's legacy has begun to hurt Santorum is a microcosm, some said, for how the former Republican president negatively impacted the conservative movement as a whole.
"Santorum is a perfect example of what Bushism did to the Republican Party," said a former Senate GOP aide with detailed knowledge of Santorum's work in GOP leadership, who feels Santorum "undermine(d) fiscal conservatives."
Many conservatives see No Child Left Behind, along with Bush's expansion of Medicare and his failure to veto any spending bills for most of his presidency -- while Republicans controlled Congress -- as betrayals of conservative belief in limited government. They believe Bush accelerated a trend of expanding the federal government that has in turn been sped up by President Barack Obama.
A win for Santorum in next Tuesday's Michigan primary would be a game-changer, badly wounding Romney and thrusting Santorum forward into the driver's seat. But Santorum's Bush association is one of the major factors -- past statements on social issues is the other big one -- that has been a drag on his momentum this week, as Romney has moved to make up ground in the polls.
Yet Andrew Card, who was Bush's White House chief of staff from 2001 to 2006, said that Santorum was not an automatic Bush ally in every fight.
"He was not always a dependable vote to be honest with you. We had to work hard for it," Card told The Huffington Post. "But he listened well and gave us the benefit of the doubt when we came to him with a challenge."
On No Child Left Behind, Card said he "put Rick in the leaning favorable-skeptic category" going into the effort to pass the legislation. Santorum's caution, Card said, was based on concerns about the federal government's role in education.
"I still think it's the right policy," Card, currently acting dean of The Bush School of Government and Public Service at Texas A&M University, said of the law.
"It didn't always get implemented to live up to people's expectations. But it was a noble and historic reform that was brought into education that you were going to hold people accountable and have some measure of success," Card said. "It did crack the establishment to bring more accountability to it."