Travel plans for Senator Barack Obama’s running mate, Senator Joseph R. Biden Jr., have yet to be finalized beyond his arrival this week in Denver for the Democratic National Convention. But campaign advisers said Sunday that they were certain Mr. Biden would spend considerable time campaigning through Election Day in four swing states: Florida, Michigan, Ohio and Pennsylvania.

Mr. Biden has developed close ties with unions of firefighters and police officers and the Teamsters in his nearly 36 years as a senator from Delaware. He is well known and liked in Ohio and Pennsylvania. Roman Catholics and working-class Democrats count him as one of his own. He has many Republican friends: He wrote a blurb for a book by Senator Arlen Specter of Pennsylvania, and Senator Chuck Hagel of Nebraska wore a Biden mask last Halloween.

And Mr. Biden’s staunch support for Israel, most recently as chairman of the Senate Foreign Relations Committee, is also expected to help Mr. Obama with Jewish voters in Florida and elsewhere, Obama advisers said.

“It makes sense that he will campaign in the battlegrounds where people are most familiar with him,” said David Axelrod, the Obama campaign’s chief strategist. “But he also has broad appeal because of his passion about how badly this country needs change, and that’s not just a Catholic message or Jewish message or Rust Belt message.”