WASHINGTON — In an attempt to rally the Republicans before the midterm elections, President Bush enlisted the aid of America’s foremost “shock jock” yesterday, taking to the airwaves to remind millions of conservative listeners of what may happen if Democrats regain control of Congress.

The president’s appearance on Rush Limbaugh’s show was part of a Republican strategy to bypass the “mainstream media” and appeal directly to Mr. Bush’s most loyal supporters.”Thank you, sir, for giving me a chance to visit with you,” he told Mr. Limbaugh.

Republicans can only avoid heavy losses next week if their core support remains motivated to go to the polls. A Democratic takeover of Congress risks leaving Mr. Bush as a lame-duck president for his final two years in office. Mr. Limbaugh gave the impression that such an event would amount to mass treason.

Campaigning in marginal districts is problematic for an unpopular president whose presence risks motivating Democrats to vote against Mr. Bush. But liberals do not listen to Mr. Limbaugh’s show, allowing the president to pursue an “on the air but under the radar” strategy to boost GOP morale.