By Caren Bohan
CAMBRIDGE, Maryland (Reuters) - President Barack Obama vowed on Friday to push back hard against Republicans who try to obstruct his election-year proposals on taxes and jobs, as he sought to rally congressional Democrats and move past a period of strained relations.
Wrapping up a cross-country tour to promote a populist agenda laid out in this week's State of the Union address, Obama hammered home a reelection campaign appeal for greater economic fairness and called on fellow Democrats to close ranks with him.
Obama, who must convince voters to give him a second term despite a fragile economy and high unemployment, used his speech to a Democratic lawmakers' retreat in Maryland to turn up the heat on their Republican opponents.
Republicans accuse him of pursuing the "politics of envy" and have assailed his State of the Union proposals, including higher taxes on wealthier Americans.
"Where they obstruct, where they're unwilling to act, where they're more interested in party than they are in country ... then we've got to call them out on it," Obama said to loud applause. "We've got to push them. We can't wait. We can't be held back."
The White House believes that by casting Obama as a champion of the middle class, he can tap into voter resentment over income inequality and Wall Street excess, while painting the Republicans as the party beholden to the rich.
But Obama's economic proposals are unlikely to make headway in a deeply divided Congress, where Republicans control the House of Representatives and the president's legislative agenda remains stalled.
Pledging to "push hard" for his proposal that people earning more than $1 million a year pay a minimum of 30 percent in tax, Obama dismissed Republican criticism this was class warfare.
"Nobody envies rich people. Everybody wants to be rich ... the question is, are we creating opportunity for everybody?"
Relations between Obama and Democratic lawmakers suffered after Republicans won the House in the 2010 congressional elections, with some Democrats complaining Obama had made too many concessions to his political opponents.
But ties have improved in recent months as Obama has taken a more combative line toward Republicans over taxes and jobs and has drawn a stark contrast with Republican presidential hopefuls vying to face him in the November election.
Starting his appearance with a standing ovation from the audience, Obama thanked the House Democrats for giving him a compact disc in which they all performed a rendition of Al Green's 'I'm So In Love With You.'"
(Additional reporting by Alister Bull and Matt Spetalnick in Washington and Thomas Ferraro in Cambridge, Maryland; Editing by Eric Walsh)