Mr. Bush is campaigning in Georgia and Texas this week, as his political advisers balance the need to help Republicans in tight races against the president's unpopularity.
Polls show Democrats have a shot at gaining the 15 seats they need to win the House of Representatives, and may even win the six needed to take the Senate. All 435 House seats and 33 in the 100-member Senate are up for a vote next Tuesday.
"For decades, activist judges have tried to redefine America by court order," Mr. Bush said Monday in Statesboro. "Just this last week in New Jersey, another activist court issued a ruling that raises doubt about the institution of marriage. We believe marriage is a union between a man and a woman and should be defended."
The line earned Mr. Bush by far his most sustained applause at a rally of 5,000 people aimed at boosting Republican former Congressman Max Burns' effort to unseat a Democratic incumbent. In this conservative rural corner of eastern Georgia, even children jumped to their feet alongside their parents to cheer and clap for nearly 30 seconds — an eternity in political speechmaking.
The New Jersey Supreme Court ruled that same-sex couples must be given all the benefits of married couples, leaving it up to the state Legislature to decide whether to extend those rights under the structure of marriage or something else, such as civil unions.
"I believe I should continue to appoint judges who strictly interpret the law and not legislate from the bench," the president said, earning more applause in the sweltering basketball arena at Georgia Southern University.
With just a week and a day to go until Election Day, this is just the second rally of the campaign for Mr. Bush following many closed fundraisers, CBS News White House correspondent Peter Maer reports.
As Democrats try to make the president the issue, the White House insists campaign finance law restrictions and not any candidates' reluctance to appear with him curtailed the number of open events. Now both parties are trying to energize core supporters to turn out a week from tomorrow.
To that end, Mr. Bush was focusing on the South in the last days of the campaign.
After campaigning for Burns, who is trying to win back the seat conservative Democrat John Barrow took in 2004, Mr. Bush was flying to Texas to campaign for the Republican candidate for the seat vacated by Tom DeLay, the former No. 2 Republican in the House of Representatives. DeLay resigned in June amid a series of investigations of his fundraising activities.
An afternoon rally at the airport in Sugar Land, Texas, was expected to draw 7,000 people to support Republican Houston City Councilwoman Shelley Sekula-Gibbs' campaign to replace DeLay.
Mr. Bush's need to appear in the conservative district south of Houston underscores the Republicans' plight this election.
The election there is complicated. The Republicans are legally barred from replacing DeLay's name on the ballot, so Sekula-Gibbs is running as a write-in candidate. Supporters must choose her twice, once for the special election filling out DeLay's term and again for the general election for the next Congress.
She faces Democratic former congressman Nick Lampson, who has outraised and outspent her, giving Democrats a chance at a seat long in Republican hands. A Lampson victory could help Democrats gain control of the House, and would also be sweet revenge for an opposition party that DeLay fought at every turn while in office.
On Tuesday, Mr. Bush is heading back to Georgia, a state he twice won comfortably. Tuesday's rally is aimed at helping another Republican former congressman, Mac Collins, oust Democratic Congressman Jim Marshall.
On Monday, Mr. Bush pleaded with Republicans not to give up — and mocked Democrats.
"This election is far from over," he said. "You might remember that about this time in 2004, some of them were picking out their new offices in the West Wing (of the White House). The movers never got the call."
Democrats ridiculed him back for an itinerary that took him to once-solid Republican areas.
"Clearly President Bush is more of a liability than an asset as he's forced to (campaign) for candidates in districts that were once considered safe for Republicans," said Democratic National Committee spokeswoman Stacie Paxton. "Voters in Georgia and Texas, like all Americans, are tired of President Bush's failed 'stay the course' rhetoric on the economy and Iraq."