Built to dominate the enemy in combat, the Army's hulking Abrams tank is proving equally hard to beat in a budget battle.

Lawmakers from both parties have devoted nearly half a billion dollars in taxpayer money over the past two years to build improved versions of the 70-ton Abrams.

But senior Army officials have said repeatedly, "No thanks."

It's the inverse of the federal budget world these days, in which automatic spending cuts are leaving sought-after pet programs struggling or unpaid altogether. Republicans and Democrats for years have fought so bitterly that lawmaking in Washington ground to a near-halt.