Washington (CNN) -- In a rare display of frustration, President Barack Obama insisted Tuesday that liberal Democrats were holding him to an unfair standard of achievement by complaining he has conceded too much to political opponents.
At a hastily arranged news conference on his deal with Republicans to extend tax cuts and jobless benefits, Obama rejected protests by Democrats that the agreement announced Monday amounted to a political defeat.
"Because it's a big, diverse country and people have a lot of complicated positions, it means that in order to get stuff done, we're going to compromise," Obama said.
Both the landmark health care bill passed by Democrats earlier this year and the tax agreement brought benefits to the American people in the face of strong political opposition, Obama noted.
His job, he said, is to move past party politicking to do what's best for the country. Otherwise, "people will have the satisfaction of a having a purist position and no victories for the American people," Obama said.
"That can't be the measure of how we think about our public service," he said. "That can't be the measure of what it means to be a Democrat."
Despite Obama's comments, Democratic legislators continued to challenge the White House agreement with Republicans.
Democratic Sen. Sherrod Brown of Ohio said he believed Obama gave up too soon without pushing the Republicans for more concessions, while Rep. Bill Pascrell of New Jersey said the agreement showed that "Democrats in the House have obviously become irrelevant."
At the news conference, Obama characterized such criticism from his own party as short-sighted.
Discussing the health care reform bill that overhauled health insurance in the country but has failed to generate broad public support, Obama sounded incredulous that fellow Democrats could criticize the accomplishment as incomplete for failing to secure a government-funded public insurance option.
"So I pass a signature piece of legislation where we finally get health care for all Americans, something Democrats had been fighting for " for decades, but because it lacked a public option, "that somehow that was a sign of weakness and compromise," Obama said.
By comparison, he noted that when Social Security started under President Franklin Delano Roosevelt, it only applied to "orphans and widows."
"You did not qualify," he told reporters questioning his willingness to fight for policies he favors. Obama also noted that Medicare, the government-run health insurance for senior citizens, also started much smaller than the eventual program today.
"Under the criteria that you just set out, each of those were betrayals of abstract ideals," Obama said.
"This country was founded on compromise," he continued. "I couldn't go through the front door at this country's founding. And, you know, if we were really thinking about ideal positions, we wouldn't have a union."
Obama challenged Democrats to consider the overall impact of his first two years in office, rather than focusing on individual political skirmishes.
"I don't think there's a single Democrat out there who, if they looked at where we started when I came into office and look at where we are now, would say that somehow we have not moved in the direction that I promised," Obama said, adding: "There's not a single thing that I've said that I would do that I have not either done or tried to do. And if I haven't gotten it done yet, I'm still trying to do it."
He concluded by offering guidance to friends and foes.
"To my Democratic friends, what I'd suggest is let's make sure that we understand this is a long game. This is not a short game," Obama said. "And to my Republican friends, I would suggest, I think this is a good agreement because I know that they're swallowing some things that they don't like as well. And I'm looking forward to seeing them on the field of competition over the next two years."