WASHINGTON – It’s the “so-called Republicans” versus the “New York City elitists” in rival ads that expose a growing rift between the Republican Party’s conservatives and moderates over President Bush’s tax cut proposals.

The Club for Growth, a conservative, tax cut advocacy group, leads off Saturday with TV ads in Columbus, Ohio, and Portland and Bangor, Maine, aimed at two GOP senators, Ohio’s George Voinovich and Maine’s Olympia J. Snowe. Their opposition effectively thwarted party leaders’ efforts to win approval of a larger tax cut.

The ads equate the actions of these “so-called Republicans” to the obstacles raised by France to the U.S. war effort in Iraq. Voinovich is pictured next to a waving French flag.

“These Franco-Republicans are as dependable as France was in taking down Iraqi dictator Saddam Hussein,” Club for Growth president Stephen Moore said in a statement.

On Sunday, the Republican Main Street Partnership, representing some 65 moderate GOP lawmakers and governors, plans to counterattack with a newspaper ad in Portland defending Snowe and characterizing the Club for Growth as “misinformed New York City elitists.”

“No one who stands her ground while crafting a budget should have her patriotism challenged,” reads the ad. The partnership also plans to run TV ads in Maine for Snowe, one of its members, in the next few weeks.

Sarah Chamberlain Resnick, the partnership’s executive director, said the Club for Growth was trying “to weed out Republicans who don’t meet their litmus test from serving in both Congress and the Bush administration.” She said the Club For Growth’s ads were tasteless.

Moore, in an interview, said his group was questioning the economic judgments of Snowe and Voinovich, not their patriotism. “This is really an important party loyalty vote,” he said. “We should have total party unity on tax cuts.”

Snowe’s spokesman, Dave Lackey, noted that Snowe was one of the first senators to support the president’s Iraq policies and that attempts to link Snowe to current anti-French feelings could backfire in Maine, where many people are of French origin. “It’s a case of clearly not knowing the audience,” he said.

Discord within the Republicans, better known for maintaining unity when Democrats are in disarray, broke into the open a week ago when the House and Senate agreed to a budget blueprint for fiscal 2004 that outlined a $550 billion tax cut over 10 years.

That was less than Bush’s desired amount of $726 billion but still too high for Snowe and Voinovich, who joined Democrats in questioning big tax cuts at a time of war and rising budget deficits. To win their votes in the Senate, where Republicans hold a slim 51-49 margin, GOP leaders promised that the Senate would not go higher than $350 billion in the actual tax cut bill to take shape next month.

House Republicans were irate that their Senate colleagues had cut a deal without informing them.

“This goes right to the heart of our ability to work together,” House Majority Leader Tom DeLay, R-Texas, said after hearing of the deal. “It’s very disturbing.”

During a stop in Portland on Thursday, Snowe told reporters she was prepared to accept bigger tax cuts only if they could be offset by closing tax loopholes or finding savings in the federal budget.

In defense of her position on the $350 billion tax cut, she said the amount was significant and would provide quick stimulus to the economy.

“The key is getting the money out now,” Snowe said. “It will get money in people’s hands so they can make capital investments.”

The Club for Growth has become a potent fund-raiser for like-minded fiscal conservatives since its founding in 1999, occasionally targeting GOP moderates for defeat.

In last year’s election the group unsuccessfully backed a Republican challenger to seven-term Maryland moderate Wayne Gilchrest, and it is now promoting the campaign of Rep. Pat Toomey to unseat moderate Pennsylvania Republican Sen. Arlen Specter. It is also urging conservative Rep. Jeff Flake, R-Ariz., to challenge Sen. John McCain, another Republican Main Street Partnership member and frequent critic of White House policies.