WASHINGTON — Without naming Senator McCain, President Bush marshaled the conservative wing of the Republican Party today to back the presumed Republican presidential nominee for the upcoming battle against the Democratic Party.

“The stakes in November are high. This is an important election. Prosperity and peace are in the balance,” Mr. Bush told about 2,000 people attending the Conservative Political Action Conference. “So with confidence in our vision and faith in our values, let us go forward, fight for victory and keep the White House in 2008.”

Mr. Bush spoke to a boisterous crowd shortly after 7 a.m. The ballroom erupted in cheers when someone shouted “Are there conservatives in the house?” When the president walked on stage, they clapped and chanted “Four more years! Four more years!”

Mr. Bush reached his lowest approval rating in The Associated Press-Ipsos poll today as only 30% said they like the job he is doing, including an all-time low in his support by Republicans. Still, the crowd gave him standing ovations, cheering his comments on tax relief, the military buildup in Iraq, the Reagan years, and his opposition to abortion. They booed when Mr. Bush said his critics want to expand the size and scope of the federal government.

Conservatives are resigned to seeing Mr. McCain lead the Republican ticket in November, but they are concerned that he has a long history of disputes over economic and social issues with the party’s right flank. And it remains unclear how many conservative voters will stay at home in November or try to influence Mr. McCain’s positions — and his choice of a running mate.

Mr. Bush is not ready to weigh in formally on the election, even though Mitt Romney announced yesterday that he was suspending his campaign, virtually sealing the nomination for Mr. McCain. The president is, however, priming the conservative base to get ready to back Mr. McCain.

“We have had good debates and soon we will have a nominee who will carry a conservative banner into this election and beyond,” Mr. Bush said.

“I’m absolutely confident that with your help, we will elect a person who shares our principles,” the president said.

Mr. McCain claims he is a true conservative and has lined up the endorsements of many conservative political leaders. But one of the nation’s most prominent evangelical Christian leaders, James Dobson, backed Michael Huckabee’s presidential bid last night. Mr. Dobson reiterated his declaration on Super Tuesday that he could not in good conscience vote for Mr. McCain because of concerns over the Arizona senator’s conservative credentials.

The Senate republican leader, Mitch McConnell, Republican of Kentucky, was straightforward in expressing his support for Mr. McCain.

“I’ve had some disagreements with John McCain over the years, but he’s my friend,” Mr. McConnell said. “More importantly for this race, he’s a conservative. And he has my full support.

“When Americans see what the liberals are offering this year, we’ll win again,” Mr. McConnell said, adding that eight years ago, Mr. Bush “showed the Clintons the door.”

“With the help of you all, we’re going to make sure they stay out,” he said.