From the moment George W. Bush began campaigning for the Oval Office in 1999, White House watchers have wondered what kind of president he would be: The Ronald Reagan of his generation? Like his father, the first President Bush? Perhaps even, in some ways, similar to Bill Clinton?

This year's State of the Union address, which was panned by a chorus of conservative commentators, has intensified the debate about Bush's political philosophy.

The Wall Street Journal editorial page accused President Bush of playing "miniball," code for a Clintonian love of "small political ideas." Robert Novak reported private concern among congressional conservatives that Mr. Bush was moving toward bigger government. George Will called Bush's most memorable line - that America is addicted to oil - "wonderfully useless."

"He's conservative by temperament; many of his policy positions, such as cutting taxes, are on the right side of the political spectrum," says John Green, a political scientist at the University of Akron in Ohio. "But he doesn't have a consistent set of conservative principles. That's what a lot of the complaint has been about, especially after the State of the Union."

Specifically, Bush's education initiative, No Child Left Behind, and the expensive new prescription-drug benefit for seniors have left many conservatives wondering whatever happened to the party's commitment to small federal government. Bush's immigrant guest-worker program also divides Republicans. And as the Iraq war drags on, so, too, are conservatives increasingly conflicted.

Columnists, of course, aren't usually running for election, or trying to protect their party's slim majority in Congress, as Bush is doing. And they often don't represent the views of rank-and-file voters. A Gallup poll of State of the Union watchers, two-thirds of whom were Republicans, showed a 75 percent positive rating, including 48 percent who were "very" positive.

But pundits can also be the canary in the coal mine. When Bush nominated his counsel Harriet Miers to the Supreme Court, conservative columnists raised doubts about her reliability on key issues. Her nomination was withdrawn.

Richard Viguerie, the direct-mail guru who helped fuel the Reagan revolution of 1980, asserts that Bush's inconsistency as a conservative has alarmed many of the most active members of the party - the donors, fundraisers, and grass-roots activists who drive turnout on election day. A recent online poll by Mr. Viguerie of more than 1,000 conservative activists found that 67 percent say Bush is not governing as a conservative, and 64 percent give him a D or an F on government spending.

Even though Bush won't be on the ballot, conservative disappointment in him could hurt the Republican Party in this November's midterm elections, he says.

"The party has been hijacked by big-government Republicans," says Viguerie, hinting that it might be good for the party to lose congressional power later this year. "The importance of losing elections is greatly underrated," he adds. "There's not any way Ronald Reagan would have been elected in 1980 if [Gerald] Ford had been elected in '76."

Among conservative columnists, perhaps one of the president's staunchest admirers is Fred Barnes, editor of the Weekly Standard. In his new book, "Rebel-in-Chief," he delves into the tricky terrain of defining Bush's philosophy as president. "Big-government Republican" doesn't capture Bush, he suggests, nor do comparisons to recent presidents.

"His strategy is to use government as a means to achieve conservative ends," Mr. Barnes writes. Thus, instead of trying to abolish the Department of Education, the Reagan-era position, Bush has sought to achieve the conservative goal of accountability in public education by requiring testing and then sanctions for schools that fail to meet standards.

Mr. Barnes separates presidents into two categories - those who govern and those who lead. He places Bush in the latter category, observing his penchant for far- reaching initiatives. Looking at the issue of presidential temperament, Barnes writes, "Bush is actually a mixture of FDR [Franklin Delano Roosevelt] and TR [Teddy Roosevelt], with FDR's cool optimism and TR's pugnacity and determination."

Drawing any sort of comparison between Bush and the Roosevelts strikes some presidential historians as off-base, but on one score, at least, even Bush's critics credit him with a level of political pragmatism that keeps him in the game. Take the failed initiative to partially privatize Social Security. While conservative columnists scolded Bush for taking his top domestic priority of 2005 and reducing it to a call for a bipartisan commission on entitlements, other analysts say he was just being realistic.

"He's going to go back and try pushing his Social Security idea again?" asks historian Robert Dallek. "It won't go anywhere. It was a political blunder."

Another factor that may hurt Bush somewhat in the eyes of conservatives is the memory of Reagan, which grows more positive as time passes. Even though Reagan never actually succeeded in shrinking the federal government, his campaign against big government delighted libertarians and fiscal hawks, who now complain that Bush has abandoned that legacy. Federal spending leaped 35 percent during Bush's first term, the Cato Institute notes.

"We hoped [Bush] would be more like Reagan than his father, but clearly he is not like Ronald Reagan," says Viguerie. "Reagan was no pure conservative - he wandered off the conservative reservation here and there. But there was such a massive reservoir of goodwill for Reagan, because he was one of us. He walked with us and came to our meetings and receptions and dinners and sat with us."