President Bush will likely cast the first veto of his presidency if the Senate, as expected, passes legislation to expand federal funding of embryonic stem-cell research, White House aide Karl Rove said today. "The president is emphatic about this," Rove said in a meeting with the editorial board of The Denver Post. The U.S. House of Representatives has already passed the legislation, co-sponsored by Rep. Diana DeGette, D-Denver, and Rep. Mike Castle, R-Del. If the Senate approves the bill this month it would go to the president's desk.