While Presidents of both parties have demonstrated over the years that they can deploy U.S. military troops without involving Congress, sooner or later, the purse strings get involved.

And we may see that in just the next few weeks when it comes to Libya.

Remember - the budget for the current fiscal year hasn't been finished. Congress has until April 8 to approve either a long term spending plan, or another temporary budget extension to keep the government running.

In other words, there will be a budget bill on the floor of the House and Senate in coming weeks which could provide the chance for a vote in relation to the Libya mission.

"We have already spent trillions of dollars on the wars in Iraq and Afghanistan," complains Rep. Dennis Kucinich (D-OH), who argues Libya could turn into an expensive bottom line.

"Now, the President is plunging the United States into yet another war we cannot afford," the liberal Democrat added, as he vowed to force a vote on block money for the Libyan mission.

It's a familiar battle, but even those who have worked here on Capitol Hill have forgotten past skirmishes along these lines, as Presidents flex their muscles against the Legislative Branch's explicit power to declare war.

Korea and Vietnam are perfect examples. President Truman never got the okay of Congress for the Korean War. Vietnam had the Tonkin Gulf Resolution, but later it was not seen as an explicit authorization for the use of U.S. forces.

In 1983, the Congress didn't authorize a military invasion of Grenada. The same thing happened in 1989 when President George H.W. Bush sent U.S. troops into Panama, spurring criticism from Democrats.

The shoe was on the other foot in 1994 over President Clinton's plans to send troops to Haiti and Bosnia without authorization of the House and Senate.

As I like to say, we just repeat history in the Congress, while very few remember what went on just a few years ago.

We have had times when approval of the Congress was sought by the White House, like for the war against Iraq in the first and second Bush Administrations, as well as a use of force resolution against terrorists in the wake of the Nine Eleven Attacks.

But that certainly did not mitigate the political fallout in the George W. Bush Administration.

Congress does have an option in all of this. They can block the military from spending money on the Libyan mission, just like lawmakers did with Vietnam:

"Sec. 108. Notwithstanding any other provision of law, on or after August 15, 1973, no funds herein or heretofore appropriated may be obligated or expended to finance directly or indirectly combat activities by United States military forces in or over or from off the shores of North Vietnam, South Vietnam, Laos or Cambodia."

We also saw the same approach in the 1980's, when the Congress finally moved to cut off aid by the Reagan Administration to the Contras in Central America.

We'll see if Congress really takes that approach or not. Sometimes there's a lot more bluster than action out of lawmakers in both parties.