President Bush said members of Congress need to be thrifty with the federal budget.
And he said they must avoid temptations to leave education and defense bills until last.
"There is a temptation not to listen to the budget in the first place," Bush said. "We don't want the budget to be a hollow noise. We want the budget to be real."
Bush told a crowd in Harry Truman's hometown of Independence, Mo., Tuesday that the federal budget has enough money for his tax cut and bolstering the military, Social Security and Medicare.
"There are some who say tax relief is going to make it hard to meet the budget," Bush said at Harry S. Truman High School. "But the reality is it will boost the economy. I trust you. I would rather you spend your money than the federal government spend your money."
His speech was aimed at shifting pressure to Congress as the White House Office of Management and Budget prepares to report how big this year's budget surplus will be. Because of the tax cut and slowing economy, the report is expected to show that the current-year surplus has plummeted to roughly $160 billion from the $284 billion projected in April.
Bush went through a list of his initiatives and defended his plan, calling on Congress not to overspend.
Democrats were responding with a television advertising campaign that said Bush's budget "violates one of Harry Truman's basic principles — protecting our seniors. The Bush budget raids the Medicare trust fund. Now he's using gimmicks to hide a raid on Social Security."
The spots, prepared by the ad campaign team used by former Vice President Al Gore, will run in about a half dozen cities including Independence; Waco, Texas; and Washington, according to Democratic National Committee spokeswoman Jennifer Palmieri.
The White House acknowledged that budget projections to be released Wednesday will show that the surplus in Medicare Part A, which pays for seniors' hospital visits, has been depleted.
But Karen Hughes, counselor to the president, argued that the numbers do not mean Bush broke his promise to protect Medicare because they used the Part A fund to cover doctor visit benefits in Medicare Part B, which has been in deficit.
"The Democrats' logic is they will fund only the hospital part of Medicare, not the doctors' part, and we think we should pay both," Hughes said.
Bush reiterated his call for partial privatization of Social Security.
"Soon, there are not going to be enough people paying into the system," Bush said. "One of the reasons I am standing here is because I had the courage to tell that message. We must give younger workers the option to manage their money in the private sector if that's what they choose to do."
Outside the high school, there were equal numbers of supporters and protesters among the dozens who lined the roads of Independence. Some hand-written signs made reference to the president's tax cut, "Thanks for the rebate." Others referred to last year's bitter election recount battle with Gore: "Get out of Al's house!" and "Undo the coup."
Bush also pitched his plan to allow churches and religious groups to apply for federal money for social programs.
"Part of this is loving your neighbor like you'd like to be loved yourself," he said to loud applause. "I don't believe America should fear faith, it should welcome faith-based programs."
The Associated Press contributed to this report.