With two days left before U.S. midterm elections, polls indicate opposition Democrats could take control of the 435-member House of Representatives, but control of the Senate is less clear.
President Bush is campaigning in (the western U.S. states of Nebraska and Kansas on Sunday - part of a cross-country swing to show support for Republican Party candidates.
Some analysts predict significant election-day losses for the ruling Republicans, mainly because of widespread voter dissatisfaction with Iraq.
A recent CBS news network poll indicates the Iraq war is the most important concern of voters, followed by the economy and jobs, illegal immigration, and terrorism.
Mr. Bush on Saturday said the United States will not run from what he called the central front in the war on terror. He also said opposition Democrats had no plan for improving the situation in Iraq.
Democrats say a Democratic Party majority in Congress would result in a change in strategy in Iraq.
All House seats are up for election every two years. About one third of the Senate seats are being contested.