CANNON FALLS, Minn. — For most of the summer, President Obama has been under siege in the White House. On Monday, he became a road warrior, kicking off a three-day bus tour of the Midwest that provided him campaign-style opportunities to strike back at Republicans in a region vital to his re-election.

Traveling in a black bus with dark tinted windows and flashing red and blue lights that looked like something out of a “Mad Max” movie, the president urged audiences in Minnesota and Iowa to tell their elected officials they would no longer tolerate the partisan gridlock on display in the recent debt-ceiling talks.

“You’ve got to send a message to Washington that it is time for the games to stop,” he told a crowd of 500 under a canopy of elm and black walnut trees here.

“It’s time to put country first,” he said, recycling a line used by his Republican opponent in the 2008 presidential race, Senator John McCain of Arizona.