WASHINGTON — President Obama's nominee to be the Pentagon's top weapons buyer said Thursday he supports a proposal in Congress that would place greater scrutiny on defense contracting to cut down on runaway costs for big programs.

Testifying during his nomination hearing before the Senate Armed Services Committee, Harvard professor Ashton Carter said there was "no silver bullet" to solve problems that include schedule delays, large budget overruns and a sharp decline in competition among a shrinking number of defense contractors that supply most of the military's weapons.

But Carter told lawmakers his job at the Defense Department as the acquisitions undersecretary would be to "get under control the many troubled programs" that have led to growing calls for reform of the Pentagon's acquisition methods.

"Too many of these (weapons) programs are failing their cost, performance and schedule expectations," Carter said.

Committee Chairman Carl Levin, D-Mich., and its ranking Republican, John McCain of Arizona, have proposed legislation that would require more rigorous reviews of defense contracts. It would include more scrutiny in earlier stages of weapons development, appoint a new official to evaluate program costs and try to ensure that weapons actually work before the Pentagon buys them.

Obama cited the legislation during a prime-time news conference on Tuesday, and his fiscal 2010 defense budget includes language meant to reform military contracting. Many analysts believe some big programs could face funding cuts as a result, such as the Army's modernization program led by Boeing Co. and parts of the Pentagon's missile defense program that includes most of the nation's big contractors.

Trained as a physicist, Carter currently teaches at Harvard's Kennedy School of Government. He also served as a top Pentagon official for nuclear weapons policy during the Clinton administration.