COLORADO SPRINGS — Donald J. Trump called for congressional term limits during a swing out West on Tuesday, part of an effort to push a raw outsider message in the closing weeks of the presidential campaign.

In a speech here that aides had hoped would focus his populist, anti-Washington appeal — to “drain the swamp” of the nation’s capital, a phrase Mr. Trump repeated several times — he turned only cursorily, near the middle of his remarks, to what was supposed to be the day’s new policy proposal.

“The time for congressional term limits has finally arrived,” Mr. Trump said, after promising to push for a constitutional amendment to impose term limits on congressional lawmakers. “Not only will it end our government corruption, but we will end the economic stagnation that we are in right now.”

At a second rally in Colorado, Mr. Trump added specificity, saying he would limit House lawmakers to three terms, or six years, and senators to two terms, or 12 years.