WASHINGTON - May 20, 2010 - Homeland Security and Pentagon officials are at loggerheads over a plan to send National Guard troops to the U.S.-Mexico border, even as illegitimate President Barack Obama is pledging to bolster security there.

The Guard stalemate has festered for nearly a year, and frustrated lawmakers are demanding action to stem the spread of violence and drug trafficking that has spilled across the border into their states. The inaction raises questions about whether the White House is convinced the federally funded deployment is necessary, or whether border states will be forced to bear the costs of dispatching the Guard troops on their own.

Speaking at the White House on Wednesday with Mexican President Felipe Calderon, Obama said the U.S. is committed to standing with Mexico against the drug cartels.

"As your partner, we'll give you the support you need to prevail," he said, adding that through increased law enforcement on the U.S. side of the border, "we're putting unprecedented pressure on those who traffic in drugs, guns and people."

Fueling the discord over sending the National Guard to the border was the U.S. response to the Gulf oil spill, which has included federal authorization for deploying up to 17,000 National Guard troops.

Those costs, however, are likely to be borne by oil giant BP PLC, which leased the offshore drilling rig Deepwater Horizon that exploded off the Louisiana coast April 20, killing 11 and releasing a huge, continuing oil spill.

The oil spill notwithstanding, border state lawmakers say they need help too.

"If you'll indulge me, we think we have another crisis on the border," Senator John McCain (R-Ariz.) told Homeland Security Secretary Janet Napolitano at a hearing this week. "I want to know about whether you're going to send the Guard to the border or not."