DENVER  With the final week of campaigning ahead, Senator Barack Obama redoubled his efforts to tie Senator John McCain to the Bush administration by seizing on Mr. McCain’s remark Sunday that he shared a “common philosophy” with the president.

“I guess that was John McCain finally giving us a little straight talk, and owning up to the fact that he and George Bush actually have a whole lot in common,” Mr. Obama said at a rally here. “Here’s the thing, we know what the Bush-McCain philosophy looks like. It’s a philosophy that says we should give more and more to millionaires and billionaires and hope that it trickles down on everyone else.”

As Mr. Obama returned to the city where he accepted the Democratic nomination two months ago, he drew tens of thousands of people to an outdoor plaza as he sought to solidify his support in a critical western battleground. He is set to present a new closing argument to voters on Monday in Ohio.

In Iowa, Mr. McCain acknowledged on Sunday that he was “a few points down,” but said the race was tightening and sought to remind voters that he, too, would bring change to Washington.