Exclusive: Obama Would 'Rather Be Really Good One-Term President' Obama tells Diane Sawyer he doesn't want to be a "mediocre two-term president."

Jan. 25, 2010  -- President Obama, buffeted by criticism of his massive health care reform bill and election setbacks, said today he remained determined to tackle health care and other big problems despite the political dangers to his presidency.

"I'd rather be a really good one-term president than a mediocre two-term president," he told ABC's "World News" anchor Diane Sawyer in an exclusive interview today.

Obama sat down with Sawyer two days before he will deliver a State of the Union address to a joint session of Congress, and he acknowledged the political setbacks of his first year in office.

The State of the Union will be Obama's chance to jump-start his agenda, but he ducked when Sawyer asked if he could guarantee there would not be a tax increase for anyone making less than $250,000.

"I can guarantee that the worst thing we could do would be to raise taxes when the economy is still this weak," he replied.

Watch Diane Sawyer's interview with President Obama on "Nightline" at 11:35 p.m. tonight, and on "Good Morning America" at 7 a.m. Tuesday

The speech this Wednesday comes at a time when the president's health care reform bill, the centerpiece of his domestic agenda, is stalled in Congress because the Senate lost its supermajority when Massachusetts elected Republican Scott Brown last week. Brown campaigned on a promise to vote against the bill.

The president had previously admitted the convoluted process of cobbling together the huge bill had alarmed voters but said today he would not back off of tackling large issues despite the political jeopardy involved.

"You know, there is a tendency in Washington to believe our job description, of elected officials, is to get re-elected. That's not our job description," Obama said. "Our job description is to solve problems and to help people."

The president said he was not deterred by the problems with the health care bill.

Click here to read the full transcript of Diane Sawyer's interview with President Obama

"I will not slow down in terms of going after the big problems that this country faces," he said. "The easiest thing for me to do, Diane, would be to go small bore, avoid controversy, just make sure that everybody's comfortable and we only propose things that don't threaten any special interests in Washington. If you do that, then you can get a boost in the poll numbers."

Seated across from Sawyer in the White House, the president added, "I don't want to look back on my time here and say to myself all I was interested in was nurturing my own popularity."

The president's poll numbers have sagged in recent weeks as the debate over health care peaked and the economy, particularly the unemployment numbers, stubbornly resisted a quick fix. Obama dismissed the dip in his job approval rate.

"I went through this [in] the campaign. When your poll numbers drop, you are an idiot. When your poll numbers are high, you are a genius. If my poll numbers are low, then I am cool and cerebral, and cool and detached. If my poll numbers are high," Obama said with a laugh, "boy he's calm and reasoned all right."

State of the Union Speech on Wednesday

The president conceded he has made mistakes, at one point saying, "I'd probably say I make a mistake a day, maybe two." One of the biggest, he said, was the confusing way in which the health bill was shaped.

"I think the healthcare debate as it unfolded legitimately raised concerns not just among my opponents, but also amongst reporters that we just don't know what's going on," and that some "stray cats" got in the bill, he said.

But the president insisted "I didn't make a bunch of deals… I am happy to own up to the fact that I have not changed Congress and how it operates the way I would have liked."

The president's comments seem to acknowledge that the year-long fight for a health care reform bill has cost him politically. The day after Brown won election in Masschusetts, Obama indicated that he was willing to make concessions to win passage of some form of a health care reform bill.

Within days of the Massachusetts election, he has also hired his 2008 campaign manager David Plouffe to help his administration and the Democratic Party regroup before the midterm elections later this year.

The president said the setbacks suffered by politicians in Washington are "nothing compared to the setbacks of a guy who loses his job… He's sending out 100 resumes and he's not getting any answers back and his wife and kids are at home and he's thinking, am I going to be able to make sure that mortgage payments get made? Am I going to be able to afford to keep my health insurance? … They get up every day, they go out for that next interview and they keep on interviewing until they find a job. Those are the people who inspire me."

Watch President Obama's State of the Union address Wednesday on ABC News or streamed live on ABCNews.com

The White House has made it clear that during the State of the Union the president will propose measures that emerged from his Task Force on Middle Class Families.

Those measures include:

Increasing the Child and Dependent Care Tax Credit for middle class families making under $85,000 a year from 20% to 35% of qualifying expenses.

Capping student federal loan payments to 10 percent of the student's income above a basic living allowance.

Requiring all employers to give workers an option of automatic workplace direct-deposit IRAs.

Expanding tax credits to match retirement savings by expanding and simplifying the Saver's Credit to match 50 percent of the first $1,000 of contributions by families earning up to $65,000 and providing a partial credit to families earning up to $85,000.

Expanding support for families balancing work with caring for elderly relatives with a $102.5 million Caregiver Initiative.