Senate Minority Leader Mitch McConnell’s failure to reveal in advance that he would vote last week for an earmark freeze has sparked concern on the right.

Critics say that by staying silent, McConnell (R-Ky.) squandered an opportunity to woo wider support among wayward Republicans and make it appear that only Democrats defended controversial pork-barrel projects.

To many of those critics, it appeared that McConnell, a longtime appropriator who has brought many an earmark back to his home state, was playing both sides by not lobbying for the measure, which ensured that it failed, while voting for the amendment in order to insulate himself from attacks on the right.

Don Stewart, a McConnell spokesman, dismissed the talk, saying the bottom line is that the senator supported the plan after carefully evaluating its ramifications.

“What matters in the end is his vote,” Stewart said. “And everything else is just talk.”

McConnell’s careful calculation underscores his balancing act on the most divisive issue confronting his conference since last summer’s immigration debate. McConnell took a similar tack then, staying out of the immigration fight and keeping a low profile until he cast a vote to block a bill disliked by the party’s right wing.

McConnell sponsored $185 million worth of earmarks for Kentucky in fiscal 2008, and argued that Congress has the constitutional right to set spending priorities. Approaching what could be a tough reelection bid this November, the senator has highlighted “results” he has delivered for Kentucky, including the pet projects secured through the appropriations process.

But he is also facing enormous pressure from a conservative base roiled by what it sees as the wasteful Washington practice of inserting parochial spending requests into appropriations bills.

In response, McConnell established a five-member GOP task force in January to recommend reforms. Since McConnell asked for unanimity in the group’s report, to be released next month, it will certainly stop short of calling for a freeze in earmarks and will instead seek to make Senate earmarking as transparent as it is in the House under rules set in January 2007, according to two people familiar with the report’s contents.

The report, however, is likely to fuel efforts by fiscal conservatives who want Congress to use the one-year pause to implement badly needed long-term reforms.

Unlike the Senate GOP, House Republicans have rallied their conference to support a one-year earmark moratorium, so long as Democrats also agree. So far, House Speaker Nancy Pelosi (D-Calif.) has not taken a firm position on a moratorium, giving Republicans election-year fodder to use against the majority party.

Senate Republican leaders appeared hesitant to take a similar approach against Senate Majority Leader Harry Reid (D-Nev.) last week, critics say. If McConnell had taken a more visible role publicly and privately, it would have helped isolate Senate Democrats and increased votes for the plan, conservatives say.

“It would have been helpful had Sen. McConnell come out and been more forceful in advance of the vote,” said Robert Bluey, director of the Center for Media and Public Policy at the conservative Heritage Foundation.

As media attention and debate grew throughout the week, McConnell said he was studying the implications of the plan, offered by Sen. Jim DeMint (R-S.C.), and declined to state his position until after the vote occurred, just before 11 o’clock Thursday night. The Senate overwhelmingly rejected the amendment by a 29-71 vote, with 26 of the 49-member GOP Conference and a nearly united Democratic Conference voting against it.

Even if McConnell had announced his support early, as did all three presidential candidates, securing the necessary 60 votes to win adoption of the amendment appeared highly unlikely. But, according to people lobbying for the plan last week, there were as many as 30 uncommitted senators in the run-up to the vote, and McConnell’s early and vigorous support might have helped.

“It showed that aggressive support for leadership on either side of the aisle would have made a huge difference, because undecideds on this vote were so high,” said Keith Ashdown of Taxpayers for Common Sense, which supported the DeMint amendment.

“If the Republicans aggressively take the position of earmark reform, then it does put pressure on the Democrats to follow suit,” said Larry Hart, director of government relations at the American Conservative Union.

In a statement after the vote, McConnell said more steps are needed for greater transparency and accountability in the earmark process, but that Congress also has a role in spending decisions.

“I take that obligation very seriously,” he said of setting spending priorities for Kentucky, but added that new reforms should be instituted before appropriations bills start to move.

Andrew Moylan, government affairs manager at the National Taxpayers Union, said his lobbying push would have been “a lot easier” had McConnell made that announcement earlier last week.

“When I can point to the Republican leader in the Senate supporting something, you can probably convince a lot more of the moderate folks and the folks on the fence that this is a good idea,” Moylan said.

“Republicans are looking for new leaders that can inspire, communicate and rally support to our principles,” one GOP aide said.