DES MOINES -- John Sununu, the former New Hampshire governor and George H.W. Bush White House chief of staff, has emerged as a top surrogate for the Romney campaign.  His job lately has been to attack the surging Newt Gingrich.  To a remarkable degree, Sununu's critique of Gingrich is rooted in events of 21 years ago, when the first President Bush abandoned his famous "read my lips" promise never to raise taxes. What is striking is that Sununu supported -- actually engineered -- the Bush retreat, while Gingrich opposed it.  Today, nearly all Republicans remember Bush's decision as a disaster. Sununu's position is hugely unpopular with Republicans who recall the episode, while Gingrich's position is hugely popular. And yet Team Romney is making Sununu a central player in its case against Gingrich.

Just a few hours ago, the Romney campaign sent out a new attack on Gingrich, this one headlined SUNUNU: GINGRICH THREW CONSERVATIVES UNDER THE BUS.  The press release highlights Sununu's remarks Friday on conservative radio host Scott Hennen's program.

Sununu charged that Gingrich "threw [Republican Rep. Paul] Ryan under the bus" by criticizing Ryan's entitlement reform proposal. Then Sununu brought up the Bush I years. "I worked in the White House for well over three years, I watched the president I really admired, the first George Bush, deal with tough, tough issues," Sununu said.  "War and peace, as well as domestic issues, and you need a president that has the constancy, has discipline, rationality, and is able to make sure he makes the right decision…"  Gingrich, Sununu said, is more interested in promoting himself than in making the right decision.

The toughest of the tough, tough domestic issues that Bush I dealt with was taxes.  During his victorious 1988 campaign, Bush made the famous "read my lips" vow not to raise taxes. But midway through his term, Bush was under intense pressure from Democrats, and from some Republicans, to break that promise and agree to higher taxes as part of a deficit reduction plan.

Nobody used the phrase back then, but if they had, conservatives would have charged Bush (and Sununu) with throwing conservatives under the bus. Although he stayed publicly on board with the White House, Gingrich, then Republican Whip in the House (where Republicans were still the minority party), pushed back hard behind the scenes. When Bush released a statement saying that he had agreed to Democratic demands to drop the "read my lips" promise, the Washington Post reported:

House Minority Whip Newt Gingrich (R-Ga.) was preparing to hold a whip meeting on Capitol Hill when the statement was posted on the bulletin board of the White House press room. One person who walked into the room for the Capitol Hill meeting said Gingrich was "bouncing off the wall" and "ranting about the supreme stupidity" of the statement.

Gingrich's position still rankles Sununu. In a recent interview with the New Hampshire Union-Leader, Sununu charged that Gingrich "reneged" on supporting Bush's abandonment of the "read my lips" pledge. "I specifically asked Newt Gingrich if he would support it, and he said, 'yes,'" Sununu told the paper.  "The next day, for whatever reason, and nobody has ever been able to explain it to us, Gingrich decided that he was going to oppose it."

Gingrich and his allies tell a different story, insisting Gingrich did not agree to raise taxes.  But for Republican primary voters, the bottom line is this: A key Romney ally, Sununu, helped devise what Republicans remember as one of the most disastrous political and policy decisions ever, while Gingrich opposed it.  And now Romney is relying on Sununu to make the case against Gingrich.