President George W Bush will use his final State of the Union address on Monday to try to reassure nervous Americans about his economic rescue efforts and chart a course to stay relevant in his last year in power.

But politically weakened by the unpopular war in Iraq and increasingly eclipsed by the race to choose his successor, Bush will be more intent on recycling some of his old ideas than offering any bold new proposals.

His annual speech to the US Congress, broadcast live nationwide, could still be his last best chance to use the presidential teleprompter to set the tone for his waning months in the White House and to try to salvage his frayed legacy.

But sandwiched between Saturday's Democratic presidential primary in South Carolina and Tuesday's Republican contest in Florida, Bush will face the challenge of making himself heard above the growing din of the 2008 campaign.

At the top of the agenda for his seventh State of the Union address will be selling Americans on a $150 billion stimulus package he and others hope will stave off recession in an economy suffering from high oil prices and a housing slump.

He is now trying to head off efforts by some Senate Democrats to expand the plan beyond the tax rebates and business investment incentives he hammered out with House of Representatives leaders last week.

"While I understand the desire to add provisions from both the left and the right, it would be a mistake to undermine this important bipartisan agreement," Bush said in his weekly Saturday radio address.

The impetus for compromise is that no one, least of all an unpopular president nearing the end of his watch, wants to be blamed for an economic meltdown before the November 4 elections. Bush will speak on Capitol Hill at 9 p.m. EST (0200 GMT).

While the economy will be the dominant theme, Bush will also cite security gains in Iraq, funding of the AIDS fight in Africa where he visits in mid-February and efforts to combat global warming, a cause to which he was a relative latecomer.

But reflecting political realities with less a year left in office, Bush is not expected to push any major new policies, as he has in previous years with immigration and Social Security reform, two ambitious proposals that ultimately went nowhere.

"It is unrealistic to expect that this Congress is going to take on such big problems this year," White House press secretary Dana Perino said on Friday. Bush also has limited political leverage.

His approval ratings remain stuck in the low 30s, close to the worst of his presidency, and a Democratic-led Congress shows little enthusiasm for concessions to a Republican president they increasingly see as a lame duck.

The public's mood is also downcast. Four out of five Americans rate the state of the country as poor or only fair, a new Harris opinion poll showed.

Trying to preempt Bush's speech, Democratic leaders assailed him over his handling of the Iraq and Afghanistan wars, his refusal to engage diplomatically with Iran and his administration's use of the Guantanamo detention center in Cuba for terrorism suspects.

Senate Majority Leader Harry Reid urged Bush to use his speech to start restoring US "moral authority" in the world.

Bush will underscore declining violence in Iraq, which he credits to a military buildup he ordered last January before his 2007 State of the Union speech. Democratic critics say, if that is the case, he should be stepping up troop withdrawals. While many Americans are looking past Bush to who will take office in January 2009, others have started pre-judging his presidential legacy, sometimes in harsh terms.

"He is a disaster -- if not the worst president of all time, then at least the worst since Carter, Hoover or any other recent failure," Lou and Carl Cannon, authors of a book on Bush's place in history, said in a Washington Post commentary. -