Washington (CNN) -- A new poll Tuesday showed voters are willing to give Mitt Romney a fresh look now that he is the certain Republican presidential nominee, and the former Massachusetts governor picked up public backing from the top GOP leaders in the House and Senate.
The good news came as Romney's campaign offered a mild rebuke to right-wing rocker Ted Nugent's for his latest inflammatory rhetoric against President Barack Obama, seeking a middle ground between condoning divisive language and alienating conservatives who like Nugent's firebrand politics.
Obama, meanwhile, unveiled a new plan to limit oil market speculation as a way to address high gas prices angering Americans as the campaign for the November election heats up.
The CNN/ORC International poll showed that Romney's popularity is starting to rebound now that the divisiveness of the Republican primaries appears to be all but over.
According to the survey, 44% of people questioned said they have a favorable view of Romney, up 10 points from February, while 43% said they have an unfavorable opinion, down 11 points, and 13% were unsure.
According to the poll, 53% of Americans plan to give Romney a second look when the primaries are officially over, with 45% saying they already know enough about Romney to decide whether he would be a good president.
The survey indicates Romney's popularity still lags well behind Obama's: 56% have a favorable view of the president, with 42% saying they see Obama in a negative light.
"The Republican Party's favorable rating has also rebounded now that the nomination fight is all but over, from 35% in March to 41%," said CNN Polling Director Keating Holland. "That still puts the GOP several points behind the Democratic party's 46% rating, but it is an indication that the wounds have started to heal from the primary season."
Both House Speaker John Boehner, R-Ohio, and Senate Republican leader Mitch McConnell of Kentucky said Tuesday they back Romney's nomination. The statements a few hours apart were intended to show growing Republican support for Romney despite mistrust among some conservatives over his moderate policies when he was Massachusetts governor.
"I will be proud to support Mitt Romney and do everything I can to help him win," Boehner told reporters after he met with House Republicans to discuss the November election.
Romney still needs several hundred delegates to formally secure the GOP nomination, but the withdrawal from the race last week by his main conservative challenger, Rick Santorum, left Romney's path unobstructed.
McConnell later told reporters he also is backing Romney, which is no surprise but represents a formal endorsement after the Kentucky senator previously said Romney would be the party's nominee and "an excellent candidate."
Nugent, another Romney supporter, raised eyebrows this weekend when he said at an NRA convention that if Obama wins re-election in November, "I will either be dead or in jail by this time next year."
He accused the government of "wiping its ass with the Constitution" and labeled members of the Obama administration, including the vice president, attorney general and secretary of state, "criminals."
"We need to ride into that battlefield and chop their heads off in November," Nugent said.
Responding to the comments by Nugent, who announced his support for Romney last month, campaign spokeswoman Andrea Saul said: "Divisive language is offensive no matter what side of the political aisle it comes from."
"Mitt Romney believes everyone needs to be civil," Saul added.
Her reaction followed a call from Democratic National Committee Chair Rep. Debbie Wasserman Schultz of Florida for Romney to denounce comments she called "despicable, deplorable and completely beyond the pale."
"Romney's surrogates should know better than to rally the troops with outrageous rhetoric that is unacceptable in our political debate," Wasserman Schultz said in a statement.
Obama said Tuesday that the new measures he announced to limit speculation in oil markets will make amends to consumers for congressional Republicans blocking an end to subsidies for oil corporations.
"A few weeks ago, Congress had the chance to stand up for families already paying an extra premium at the pump, but congressional Republicans voted to keep spending billions of Americans' hard-earned tax dollars on more unnecessary subsidies for big oil companies," Obama said in his announcement in the Rose Garden. "So here's a chance to make amends."
Senate Republicans three weeks ago blocked a Democratic measure championed by Obama to end tax breaks for the major oil companies, which he said are enjoying record profits. Four Democrats crossed party lines to vote against the bill, but even if it had passed the Senate, it was given little chance in the Republican-controlled House.
Obama's proposal would require traders to put up more of their own money for transactions. It also would ask for more funding for market enforcement and monitoring, and increase penalties for manipulating markets.
Obama and Republicans have drawn lines over oil prices since they started to rise to near-record levels earlier this year.
Republicans say Obama hasn't done enough to stem the rise and advocate opening up more areas for drilling and approving projects like the Keystone XL pipeline, which would carry oil from Canada to refineries in Texas. But analysts say such measures would have little effect on the current price of oil and gasoline.
Most Americans blame big oil for the spike in prices -- a recent CNN/ORC International poll showed that the majority blamed the oil companies while 24% blamed Obama and 21% blamed Republican policies.
Obama's announcement came a day after one of the elements of his tax policy was blocked by Republicans in the Senate.
The so-called Buffett Rule -- named after billionaire Warren Buffett, who says the tax rate he pays should be no lower than that of his secretary -- failed to get the necessary 60 votes to go to the Senate floor. The measure would have raised the minimum tax rate to 30% for those making more than $1 million a year.
Republican presidential candidate Mitt Romney said that Obama, by pushing the Buffett Rule, shows that the incumbent is "out of ideas" on the economy.
Speaking to the Tax Day Tea Summit in Philadelphia on Monday night, Romney cited a calculation that the measure, which would have raised the minimum tax rate to 30% for those making between $1 million and $2 million, would have paid for "11 hours of government."
"This is not exactly a grand idea," Romney said. "This is a man who is out of ideas, he's out of excuses and in 2012 we're going to make sure he gets put out of office."
However, a CNN/ORC poll released Monday found that seven in 10 respondents said they favored the bill.
Romney's wife, Ann, was to be the guest of honor later Tuesday at a birthday celebration/fundraiser being held for her by Donald Trump's wife, Melania, at the couple's residence in Trump Tower in New York. Trump spokesman Michael Cohen said about 400 people were invited to the event, which was expected to bring in "well in excess" of $600,000.
Cohen said Trump will stop by the fundraiser to wish Ann Romney, who turned 63 on Monday, a happy birthday and he expects to host another fundraiser for the campaign at Trump Tower once Romney officially clinches the nomination.
First lady Michelle Obama will also be raising cash on Tuesday. She will speak at a Democratic National Committee event in Nashville, followed by two DNC fundraisers in Pittsburgh.
Romney could cross paths with the first lady when he holds a midday campaign roundtable at a community center in the Pittsburgh suburb of Bethel Park.
CNNMoney's Steve Hargreaves and CNN's Tom Cohen, John Helton, Gabriella Schwarz and Shawna Shepherd contributed to this report.