Congressional Republicans have a vested interest in President Bush’s job approval ratings, as their jobs could be in jeopardy if his numbers don’t climb back to near 50 percent come November 2006.

Republican pollster Bill McInturff said Wednesday that historical polling data suggests the president’s party could lose seats if his approval ratings remain mired in the low 40s. From 1962 to 2002, the president’s party lost an average of 43 House seats in an off-year election whenever his approval rating dipped below 50 percent.

The president’s party lost an average of 12 House seats when his approval rating was anywhere from 50 percent to 59 percent.

Bush’s “job approval rating is critical in an off-year election,” McInturff told a breakfast gathering of reporters. “When there have been wide swings in Congress, presidents have had fairly low job approval ratings.”

McInturff stressed that the political dynamics leading to this statistical relationship are much less present now than in past cycles. Among the notable differences: the ability to use issue advocacy money in Congressional races that was not legally available to Democrats in 1994, and the post-2000 redistricting that lead to a large increase in safe seats.

And with just 18 House seats carried by the 2004 Democratic presidential nominee to defend and a GOP base that continues to approve of Bush’s job performance to the tune of 81 percent, Republicans are actually in pretty good shape heading into 2006, McInturff said.

“A lot of factors make that correlation weaker today than ever before,” said the pollster, who counts 55 House Republicans and several possible GOP presidential candidates among his firm’s clients.

Democratic consultant Geoff Garin agreed that a president’s job approval rating is perhaps the biggest predictor of his party’s success in an off-year election.

Garin, without disputing McInturff’s caveats, said the predictor could be more accurate in 2006 because the Republicans control both the executive and legislative branches of government.

“Party control of Congress is not usually an important consideration in peoples’ minds,” he said. “But when people feel the country is going in the wrong direction, and one-party control is the explanation people bring to bear for that, then the issue of presidential approval ratings gets heightened in importance.”

Garin continued: “When voters are unhappy with the performance of the president, they’re much less likely to want a Congress rubber-stamping everything he does.”

Through Oct. 17, the RealClearPolitics.com average has Bush’s approval rating at 40 percent, with 54 percent disapproving.

Historical data on presidential polling shows that presidents with similar ratings — both Republicans and Democrats — lost a minimum of 26 House seats in off-year elections.

In 1982, President Ronald Reagan had a 43 percent approval rating on Election Day, and Republicans lost 26 seats. In November 1994, President Bill Clinton’s approval rating was at 46 percent, and Democrats lost 52 House seats and control of Congress.

Despite his looming impeachment, Clinton’s approval rating in 1998 was 66 percent, and his party gained five seats. Republicans, in 2002 when Bush’s approval ratings were at 63 percent, gained six seats.

Bush’s approval ratings have played a role in some of the races Democrats have targeted for 2006. Though not the sole factor, the Democratic Senatorial Campaign Committee chose to go after Sen. Jim Talent (R) in Missouri and Sen. Jon Kyl (R) in Arizona, in part because the president’s numbers in those states are poor, even though he won them in both of his presidential runs.

“What we’re seeing for the first time of his presidency is George Bush dragging down members of his party,” said DSCC Communications Director Phil Singer.

Carl Forti, who runs communications for the National Republican Congressional Committee, said that the president’s approval ratings were irrelevant to his party’s success next year.

Forti noted that polls show a majority of voters happy with their own Congressman and planning to re-elect him, even in cases where they disapprove of Congress as a whole.

“This is more important than the national atmospherics, and why we think the presidential approval numbers are irrelevant,” Forti said.

Forti also said polling shows the electorate no happier with Democrats in Congress than they are with Republicans, a fact that McInturff noted is markedly different than in 1994, when Republicans were trending positive as Democrats saw their poll numbers falling.