WASHINGTON (AP) -- President Barack Obama, setting a tough new tone for his re-election campaign, challenged Republicans on Thursday to explain to the American people why they are opposing his plan to create jobs and rebuild U.S. highways, bridges and schools as an "insurance policy" against a return to recession.
The embattled president said he had learned that he got nowhere by trying to find a middle ground in the huge partisan divide that now splits the American political system.
With Obama facing a tough re-election battle in 2012 and declining approval ratings, the Republicans see him as vulnerable and have blocked much of his legislative agenda since the party regained a majority in the House of Representatives in November 2010.
Therefore, Obama said, "I think it's fair to say that I have gone out of my way in every instance -- sometimes at my own political peril and to the frustration of Democrats -- to work with Republicans to find common ground to move this country forward."
That tactic has not worked, he said.
"Each time, what we've seen in games-playing, a preference to try to score political points rather than actually get something done on the part of the other side."
The president said that without his nearly $450 billion package of tax cuts and public works spending there will be fewer jobs and weaker growth. He said the bill could guard against another economic downturn if the situation in debt-laden Europe should worsen.
With the plan expected to come up for debate in the Senate next week, he urged every senator to think "long and hard about what's at stake."
"Any senator out there who's thinking about voting against this jobs bill when it comes up for a vote needs to explain exactly why they would oppose something we know would improve our economic situation at such an urgent time," Obama said at a White House news conference.
"Our economy really needs a jolt right now," he said.
Obama dodged a question whether he would sign a bill that is working through the Senate on trade with China. He refused to say if he supported the measure that would punish Beijing for its practice of keeping the value of its currency artificially low. That gives China a huge trade advantage by making its goods less expensive while inflating the prices of American exports.
While Obama persists in challenging Republicans, his campaign to sell the jobs proposal has not swayed congressional opponents who oppose the higher taxes that he and other Democrats want to use to pay for the proposal. They accuse Obama of playing "campaigner in chief" instead of working with them.
"If the goal is to create jobs, then why are we even talking about tax hikes?" Senate Minority leader Mitch McConnell said Thursday.
Republicans are resolutely opposed to much of Obama's jobs initiative, both for its tax increases for wealthier people and small businesses and its reprise of stimulus spending on roads, bridges and schools and grants to local governments to pay the salaries of teachers and emergency workers.
Obama did say he would support a new approach by Senate Democrats for paying for his jobs bill with a tax on millionaires rather than his plan to raise taxes on couples making more than $250,000.
Obama attempted to use Thursday's news conference to increase pressure on his congressional opponents heading into the first vote on the jobs bill that he proposed a month ago. He has been promoting it around the country ever since, often traveling into swing states or the home states of major Republicans such as House Speaker John Boehner.
"If it turns out that Republicans are opposed to the bill, they need to explain to me, and mostly importantly their constituents, what they would do," Obama said.
Obama said the economy is weaker now than at the beginning of the year. Citing economists' estimates, he said his $447 billion jobs bill would help the economy grow by 2 percent and create 1.9 million jobs.
"At a time when people are having such a hard time, we need to have an approach that is big enough to meet the moment," he said.
Obama addressed the disaffection with politics pervasive among the public that has driven down his approval ratings -- and even more so, Congress' -- as he seeks a second term.
Clearly frustrated, Obama blamed it on Republicans who he said refuse to cooperate with him even on issues where he said they once agreed with him. He talked about the ugly debate over raising the government's borrowing limit that consumed Congress and the White House for weeks, until Obama gave in to Republican demands for deep spending cuts without new taxes.
"What the American people saw is that Congress just didn't care," the president said.
Obama failed to hit hard against Pakistan, where administration officials have issued, then walked back from, a tough new line about the country's relations with groups fighting Americans in Afghanistan.
While he acknowledged "some connection" between Pakistan's intelligence operation and the so-called Haqqani network and that some in Pakistan were making alliances with "unsavory characters," Obama also said Pakistan had been "an effective partner with us."
Ten years ago the United States began its military drive to oust the extremist Taliban government that ruled Afghanistan and gave sanctuary to al-Qaida at the time of the Sept. 11, 2001 terror attacks against the United States.