Treasury Secretary John Snow, in his first full day on the job, told Treasury employees Tuesday they are "the department's most valuable resource" who needn't worry about losing major law enforcement duties to a new Cabinet agency.

"While we will miss working side-by-side with our law enforcement colleagues," Snow wrote, "this provides a tremendous opportunity for Treasury to focus on its core mission of leading our nation's economic and financial policies."

Snow's upbeat memo was to a work force that not only has lost three significant enforcement agencies but has seen its former chief fired by President Bush.

Bush picked Snow, head of the railroad giant CSX, in December to replace Paul O'Neill after the president decided to shake up his economic team in an effort to find a more effective salesman for his proposed economic stimulus package.

Snow's first major Treasury assignment began in earnest Tuesday as he went to Capitol Hill to sell House lawmakers on President Bush's plan, mostly comprising tax cuts, to energize the $10.5 trillion economy. Democrats and Republicans have been arguing over the best way to do this.

Snow comes on board as the U.S. Customs Service and the Secret Service leave their long-standing home at Treasury to become part of the new Homeland Security Department on March 1.

Last month the Bureau of Alcohol, Tobacco and Firearms, was broken up, with key duties related to guns, explosives and arson programs moving to the Justice Department. Treasury will continue to oversee tax collection and regulations involving alcohol and tobacco products.