President Obama's budget proposal will dominate the news cycle today, but how important is the document, really?

It's worth keeping in mind that the administration's budget proposal is exactly that--a proposal, a suggestion of what the White House wants Congress to spend and what it wants Congress to spend on. The legislature controls the purse strings.

ABC's Rick Klein sizes up budget day as "that annual Washington tradition of making far too much out of a proposed budget that needs to thrash its way through a Congress that has its own ideas."

When President Bush submitted his budget proposal, along with much media fanfare, to a recently Democratic Congress, I asked Rep. Jim McDermott (D-WA) what he thought of Bush's budget.

"It's basically a meaningless document," McDermott explained.

Things are different with Obama in the White House, supported by a Democratic Congress that follows his lead and will likely back his priorities; Bush, on the other hand, faced a stalemate with Congress that dragged out the budget process significantly.

Democratic lawmakers, though they support the president, will have their own ideas, as Klein points out. They will fight to get pieces of the gigantic budget pie for the initiatives they care about. Politically, Obama's budget stands as a signal of priorities, and, as Obama presented it this morning, it was an opportunity to showcase the White House's new mantras of fiscal discipline and fighting waste, call for GOP support, and admonish Republicans for opposing pay-go and a deficit commission.

But the literal, bottom-line impact of the FY-11 budget will ultimately be determined by Congress, not today's roll-out.