Lawmakers may lock heads over President Obama's massive defense spending request.

In his federal budget released today, President Obama sought $708 billion for military spending. That's $18 billion more than last year, and much more than ever requested by his predecessor George W. Bush.

Democrats in Congress may hesitate to back the president on such high spending, especially as domestic programs are cut. But some lawmakers are bound to defend the dollars, which represent contracts and jobs for their constituents, noted security expert William D. Hartung with the bipartisan New America Foundation.

The Iraq and Afghanistan wars comprise about $192 billion of the requested funds. That money will go towards troop increases in Afghanistan and ongoing efforts in both countries.

But the bulk of the funds still go to Pentagon operations and hardware, some of which are programs left over from the Cold War.

Yet strong special interests keep them alive.

Take the C-17 cargo plane and an alternative engine for F-35 fighter jets, both pricey programs President Obama tried to end last year. Congress rejected his proposal to eliminate them.

Defense Secretary Robert M. Gates will push to end those initiatives again this year, and Congress will have to decide whether to bail them out once more.

"It's pork barrel politics," Hartung said. "Members try to make strategic arguments for keeping those that benefit their states and districts."

-- Ambreen Ali, Congress.org