President Barack Obama won the public argument over taxes so decisively that almost half of Republicans now say he has an election mandate to raise rates on the rich, a poll says.

Majorities of about 2-to-1 also read the election results as an endorsement of Obama’s pledge to protect Social Security and Medicare benefits, according to a Bloomberg National Poll of 1,000 adults conducted Dec. 7-10.

And Obama confronts his first post-election test -- negotiations with Congress to avert a slate of automatic tax increases and spending cuts in January that have become known as the so-called fiscal cliff -- with his highest level of public support since his first year in office.

The president’s job approval strengthened to 53 percent from 49 percent in September. The last time he enjoyed that level of public backing was December 2009, when his job approval was 54 percent.

The combined findings give Obama “an opportunity to negotiate from a position of strength,” said Ann Selzer, the founder of Selzer & Co., a Des Moines, Iowa-based firm that conducted the poll. “This is what the public is saying he was elected to do.”

Even so, Americans expect the president to learn lessons and adjust the governing style of his first term, half of which was spent mired in partisan combat with congressional Republicans. Thirty-seven percent of Americans said Obama’s re- election validates his leadership style, while 46 percent believe he will change it.

Congressional Outreach

Alex Otey, 53, a poll respondent from Ewing, New Jersey, and a political independent who voted for Obama, said he expects the president to collaborate more with Congress in his second term.

“I think to some degree he’s going to try to find ways to work with Congress,” said Otey, a computer engineer and professional musician. “He’s either going to have to reach out more or not get anything done.”

The president’s post-election bounce cuts across party lines and covers his performance in a range of areas.

Support for Obama’s handling of the economy has surged to 48 percent from 41 percent in September and in foreign affairs to 54 percent from 45 percent. Backing of his handling of the deficit rose to 40 percent from 31 percent in March, when the question was last asked, and support for his handling of negotiations with congressional Republicans increased to 45 percent from 41 percent in March.

CEO Meetings

A 54 percent majority say the president’s recent meetings with corporate chief executive officers show he is “genuinely interested” in working with them rather than an attempt to “score political points.”

Fifty-four percent of Americans say he’s struck “about the right balance” in his relationship with business, while 33 percent say he is too anti-business and 6 percent view him as too pro-business. A 65 percent majority of Republicans say Obama is too anti-business.

The president goes into talks with Republicans amid broad public sentiment that his victory is a sign the electorate has spoken in favor of his positions on taxes and entitlements.

Sixty-five percent of Americans say the Nov. 6 results gave Obama a “mandate” on his proposal to raise tax rates on income over $250,000 and “to get it done.” Forty-five percent of Republicans agree.

Tax Mandate

The election “was basically a referendum that wealthy people could and would pay more,” said poll respondent Jim Johnson, 66, of Littleton, Colorado, a retired telecommunications executive and a Republican who voted for Mitt Romney. “It was perfectly clear. That was Obama’s stance throughout the election.”

Poll respondent Gerald Watts, 75, of Lake Quivira, Kansas, a retired engineer and another Republican who voted for Romney, read the election results the same way.

“Every time we listened to him on TV, he’d start talking about raising taxes on the rich -- every news conference, every time he went up in front of a group,” said Watts. “He didn’t want to talk about anything else.”

Even so, the differences among congressional Republicans on taxes, with Senator Bob Corker of Tennessee the latest to break from his leaders to call for raising rates on high earners, reflect a division among the party ranks. Fifty-three percent of Republicans say the election didn’t give Obama a mandate on taxes.

Entitlement Spending

Public sentiment also strengthens the president’s position on entitlements. A 64 percent majority says Obama can claim a mandate to protect Social Security from “substantial budget cuts” and 62 percent see a voter directive to prevent “fundamental change” in Medicare.

Republicans by large margins reject Obama’s victory as a mandate for his stances on entitlements. Fifty-six percent of Republicans say the election doesn’t demonstrate public support for Obama on Social Security and 58 percent of Republicans say Obama can’t claim a mandate on Medicare.

A 57 percent majority of Americans say voters gave a go- ahead on an overhaul of immigration law to provide a path to legal status for illegal immigrants, one of the administration’s priorities in its second term. Fifty-eight percent of political independents see an immigration mandate.

Republican respondents’ differ, with 63 percent rejecting the idea that Obama’s victory implies public support for legislation enabling legal status for undocumented immigrants.

Climate Change

The public is divided on whether Obama received an endorsement for his positions in favor of government action on global climate change or defense spending cuts, stances that he devoted less attention to in his campaign. Americans split an even 46 percent to 46 percent on a climate change mandate and 50 percent to 47 percent on a directive to cut the Pentagon budget.

Only majorities of Democrats see an election mandate on those two issues. Political independents reject a mandate for climate change action 49 percent to 42 percent and on defense cuts by 53 percent to 44 percent. Republicans dismissed them by wider margins, with 72 percent dismissing the idea of a mandate on climate change and 62 percent rejecting one for reducing the military budget.

As the political positioning to succeed Obama begins, Secretary of State Hillary Clinton has an advantage if she chooses to run.

Clinton 2016

Fifty-nine percent of Americans and 81 percent of Democrats rate Clinton an “excellent” or “good” potential nominee for president in 2016.

She is among the most popular members of the Obama administration with 70 percent of Americans having a positive view of the former first lady, compared with 55 percent with a favorable opinion of Obama and 48 percent with a positive view of Vice President Joe Biden.

Biden receives a positive rating as a prospective presidential nominee from 32 percent of Americans and 57 percent of Democrats.

New York Governor Andrew Cuomo, another potential Democratic nominee, is rated favorably as a nominee by 29 percent of the public and 40 percent of Democrats. Chicago Mayor Rahm Emanuel, a former Obama White House chief of staff, is rated favorably as a nominee by 19 percent of Americans and 32 percent of Democrats.

The poll of all respondents has a margin of error of plus or minus 3.1 percentage points.