President Barack Obama is keeping his calendar wide open for the final weekend before the elections so he can fly to a battleground state or two with little notice if a Democrat is in need.

Obama has stepped up his political activity in recent weeks, holding big rallies in Wisconsin, where Sen. Russ Feingold appears to be the underdog in a competitive race; Pennsylvania, where Democrats are trying to keep a Senate seat in their control; and Ohio, where both a Senate seat and governor’s mansion are leaning toward Republicans.

He’s headed to Los Angeles and Seattle this week to help Sens. Barbara Boxer and Patty Murray, respectively, and more barnstorming is likely. Obama also just recorded a radio ad for Boxer.

White House aides say that key races — including Pennsylvania — are becoming tighter, thanks in part to Obama making the case for the party on the stump. They think Democrats were dispirited throughout the year but that the base is becoming more engaged as the election nears.

A Democrat close to the White House said Oct. 30 and Oct. 31 are being held on the president’s schedule for campaign travel, with the possibility Obama could do several rallies to help get out the vote.

The source said those decisions would be made closer to Election Day, but that Pennsylvania certainly would be at the top of the list for another trip since it’s so close. A rally in West Virginia, where Gov. Joe Manchin has actively taken on the Obama administration’s agenda in his Senate race, is a lot less likely.