President Bush says cooperation with the nation's state governors is key to tackling the problems that face the country.  There are signs of frictions in one important area.

At issue is the use of the National Guard, the only branch of the U.S. military organized at the state level.

The Guard, as it is commonly called, traces its roots back to the colonial militia.  It is basically a reserve force, and traditionally members serve on a part-time basis close to home. 

Most often Guard units are under state control when they are tapped to help with natural disasters or local security issues.  But when they are called up for overseas duty they come under the command of the president.

The Bush administration has sent numerous Guard units to Iraq, and has indicated it wants to trim the number of National Guard soldiers in coming years from 350,000 to 330,000.  That has created a rift with the nation's governors.

All 50 signed a letter to the president opposing any cuts in the size of the National Guard.  The letter, which was released to the public shortly before the annual governor's meeting in Washington, urged the Bush administration to reconsider, saying Guard units must be equipped to handle their homeland security and domestic disaster duties.

President Bush did not refer directly to the dispute when he addressed the governors at the White House.  But he did praise the contributions Guard units have made to the war on terror.

"I want to thank you for supporting our Guard troops," said Mr. Bush.  "Many of you have been overseas and have seen our Guard troops in action.  And I can't thank you enough for not only supporting the troops in harm's way, but providing great comfort to their families, as well."

Later, Arizona Governor Janet Napolitano told reporters the White House did not consult with state leaders before deciding to trim the Guard.  She said that was a big mistake.

"With some of the rumors about Guard composition and so forth, the governors feel very strongly that consultation before the fact rather than after is key," she explained.

The current head of the National Governor's Association, Mike Huckabee of Arkansas, said the fate of the Guard is a particularly sensitive issue for state leaders.  He said during their stay in Washington, the governors would be discussing the matter at length with military officials.

"Certainly, they [military officials] are going to make a strong case for the idea that we can reduce the total number of Guard troops that are initially authorized, but that they will give us the ability to recruit beyond that and they will fully fund them," said Mr. Huckabee.

A defense department spokesman says the Pentagon wants to make sure the governors understand the plan to reconfigure some Guard units and move others.  He said top National Guard officers in each state were consulted before the plan was announced.