Washington ? In combative campaign form, President Barack Obama accused Republican leaders on Tuesday of becoming so radical and dangerously rigid that even the late Ronald Reagan, one of their most cherished heroes, could not win a GOP primary if he were running today.

Obama, in a stinging speech to an audience of news executives, had unsparing words for Republicans on Capitol Hill as well as the man he is most likely to face off against in November, former Massachusetts Gov. Mitt Romney. The president depicted the election as a choice between a Democratic candidate who wants to use government to help people succeed and Republicans who would abandon a basic compact with society and let most people struggle at the expense of the rich.

He framed his address around a new House Republican budget plan, saying it represents a bleak, backward “radical vision.”

“It is thinly veiled social Darwinism,” Obama said to the annual meeting of The Associated Press. “It is antithetical to our entire history as a land of opportunity and upward mobility for everybody who’s willing to work for it. … It is a prescription for decline.”

Republicans shot back that the president had offered a deeply partisan speech devoid of accountability.

Campaigning outside Milwaukee just before Obama spoke, Romney said that the president “of course will look for someone else to blame.” The Republican Party chairman, Reince Priebus, said Obama had abandoned his hope-and-change campaign slogan of four years ago. Said Priebus: “All along, he’s been a cold, calculating, big-spending politician.”

Obama’s speech removed any doubt that the general election was under way for the president, despite his professed reluctance to weigh in before Republicans settle on a nominee.

He took a couple of digs at Romney, playing up the Republican presidential front-runner’s support for a budget-slashing plan the House has approved.

That plan is doomed to die in the Senate, but Obama held it up as a sign of the disaster that would come if Republicans got their way: poor children not getting food, grandparents unable to afford nursing homes, more airline flights getting canceled and weather forecasts becoming less reliable.

By invoking Reagan, a beloved Republican, Obama sought to take GOP charges of Obama extremism and turn them back on the party. He cited a presidential debate in the current campaign in which the entire field of Republican candidates rejected the idea of $10 in spending cuts for every $1 in tax hikes if that were offered in a debt-reduction deal.

“Ronald Reagan, who, as I recall, is not accused of being a tax-and-spend socialist, understood repeatedly that when the deficit started to get out of control — that for him to make a deal — he would have to propose both spending cuts and tax increases,” Obama said. “He could not get through a Republican primary today.”