President Bush's standing with an American public anxious about Iraq (search) and the nation's direction is lower than that of the last two men who won re-election to the White House -- Ronald Reagan and Bill Clinton -- at this point in their second terms.

But solid backing from his base supporters has kept Bush from sinking to the depths reached by former presidents Harry Truman, Richard Nixon, Jimmy Carter and Bush's father. Truman decided not to run for re-election. Nixon resigned. Carter and the first President Bush were defeated in re-election campaigns.

"This president should be glad he's not running for re-election," said Karlyn Bowman, a public opinion analyst from the American Enterprise Institute. "But the president is clearly holding his base. It's very important for him to keep the base support in terms of getting things done."

Indeed, Republicans in Congress already are starting to fret about the 2006 election. If Bush's approval ratings sink lower, more of them may be unwilling to go along with his major initiatives for fear it could cause backlash for them with voters.

Bush's job approval in recent polls ranges from the low- to mid-40s. It was 42 percent in the latest AP-Ipsos poll. His ratings on everything from handling Iraq to the economy to Social Security and other domestic issues are at their lowest levels so far.

Reagan was at 57 percent at this stage of his presidency and Clinton was at 61 percent, according to Gallup polling at the time.

The partisan divide for Bush is stark -- 80 percent of Democrats disapprove of his overall performance while nearly 90 percent of Republicans approve.

Charles Black, a veteran GOP strategist and close Bush ally, said Republicans are sticking with Bush for two reasons: personal affection and loyalty.

"I haven't seen anything like it since Reagan," he said. "Bush follows through on issues that are largely popular with the base, even when it's not popular with the general public to do so."

Bush may have a hard time pushing up his numbers because issues like the violence in Iraq and gas prices are largely out of his control.

But Bush's efforts to put conservatives on the Supreme Court and overhaul the federal tax code are likely to please his conservative base.

Other presidents have seen their political bases dissolve, in Gallup poll figures:

--Truman's approval dipped to 24 percent in the late spring of 1951 after he removed popular Gen. Douglas MacArthur (search) from command in Korea.

--Nixon's approval dropped to 31 percent in August 1973 as the war dragged on in Vietnam (search) and revelations of administration misdeeds kept spilling out of the Senate Watergate hearings.

--Carter's approval plunged to 29 percent in the early summer of 1979 amid economic troubles and news of increasing problems with new Iranian leader Ayatollah Khomeini (search).

--The first Bush's approval sank to 32 percent in July 1992 as his presidential rivals Clinton and Ross Perot gained momentum in the campaign and the jobless rate rose.

For the current president to fall to those levels, Republicans and Republican-leaning independents would have to abandon him in large numbers. So far there's no indication that is happening, though there are some rumblings of discontent.

"I voted for Bush," said Jerry Fleming a GOP-leaning independent from Athens, Ala. "I feel like he's pretty much a straight-shooter as far as his religious background. I respect that part of him.

"But if the situation in Iraq keeps dragging out for a long period of time with no hope for peace, I would eventually get fed up with it," Fleming said.

For Trisha McAllister, a Republican from Grenada, Miss., Bush's willingness to ignore public opinion wins her over.

"I may not approve of every single thing he does," McAllister said, "but he's a true leader because he's not leading by the polls."

Presidential scholar Charles Jones cautioned against reading too much into low poll ratings for a president at a given point of his term.

"Truman got some of the lowest poll numbers any president ever got," said Jones, a senior fellow at the Brookings Institution. "Now when we look back on Truman, he's the highest ranked of the post-World War II presidents."