WASHINGTON — President Obama yesterday resumed his push to overhaul the health care system, telling a Congressional Black Caucus conference that there comes a time when "the cup of endurance runs over."

"We have been waiting for health reform since the days of Teddy Roosevelt. We've been waiting since the days of Harry Truman," he said in remarks at the caucus foundation's annual dinner. "We've been waiting since Johnson and Nixon and Clinton."

"We cannot wait any longer," Obama said.

Obama spent the past week focused on global and economic issues in meetings with world leaders in New York and Pittsburgh.

At the G-20 economic summit that wrapped up Friday in Pennsylvania, Obama told a story about an unnamed foreign leader who privately told the president he didn't understand the at-times contentious debate over changing the health care system.

"He says, 'We don't understand it. You're trying to make sure everybody has health care and they're putting a Hitler mustache on you. That doesn't make sense to me,' " Obama said, quoting the world leader he would not identify.

The reference to Nazi leader Adolf Hitler was to signs some people have waved outside of often testy town hall meetings around the country during the summer where lawmakers discussed Obama's health care plan.

In the speech, Obama described his plan as one that would not require people with coverage to change anything but would make health insurance affordable for the millions of people who don't have any. Republicans dispute those claims.

The Senate Finance Committee is in the process of amending a health care bill introduced by Chairman Max Baucus.

Before becoming president, Obama was the only senator in the all-Democratic caucus, which now has 42 members. He wasn't particularly active in the group and isn't especially close to many of its members.

Animosity toward the president and his policies has bubbled up in recent weeks, most notably with Rep. Joe Wilson shouting "You lie!" at Obama during the president's recent health care speech to Congress.

Democrats from former President Jimmy Carter on down have blamed the criticism of Obama on racism.

Obama says it's not racism but an intense debate over the proper role of government.