Bush made the remark at the White House Monday after a weekend where Democratic lawmakers went on the political offensive over troop reductions.
On Sunday, The New York Times reported Casey, the top U.S. commander in Iraq, is planning to send about 7,000 of the 127,000 troops home by September without replacing them, and 20,000 more would leave by the end of 2007.
That led Sen. Barbara Boxer, D-Calif., to claim that that has been the Democrats' primary goal in congressional debate in the past several weeks, CNN said.
"Here we have a situation where Democrats, 80 percent of us, voted to say we ought to start reducing our troop presence there -- and again, we got pummeled," Boxer told CBS. "And now, it turns out, we're in synch with General Casey."
All but one of the Senate's 55 Republicans and six Democrats voted Thursday against a nonbinding proposal to begin a limited troop withdrawal by the end of 2006.