President Barack Obama dished out partisan red meat today, blaming a GOP shift to the right for the gridlock in Washington, D.C., and warning that Rep. Paul Ryan’s budget plan would decimate important government programs.

In a speech to a conference of newspaper editors in Washington, Obama pitched the contrasting economic visions as the defining issue of the elections — whether the nation will double-down on tax cuts for the wealthy or continue investing in education, health care and other programs.

The Ryan budget amounted to “thinly veiled social Darwinism,” he said, and the GOP has gone so far to the right, Ronald Reagan “could not get through a Republican primary today.”

Obama noted that all of the Republican presidential candidates refused to consider even a 10-to-1 ratio of spending cuts to revenue, and he said reporters should take that into account instead of assuming that both sides are at fault for gridlock.

Obama noted that cap-and-trade started as a Republican idea, as did the individual mandate for health care.

And on taxes, Obama said Republicans are simply going along the same path that they have been — one that would keep giving tax cuts to the wealthy under the premise that they would trickle down to everyone else.

Obama said this past decade showed that doesn’t work.

“Broad-based prosperity has never trickled down. … We’ve tried their approach, on a massive scale,” he said.

Obama quoted Newt Gingrich’s statement that Ryan’s budget last year was “right-wing social engineering” and Mitt Romney’s description of it as “marvelous.”

He detailed a list of horribles he said would happen if Ryan’s unspecified cuts were applied evenly across the budget — including fewer grants for health research, science, clean energy, Head Start, food for 2 million mothers and young children, and more.

The government would be unable to properly protect the air we breathe, water we drink or food we eat, he said. Weather forecasts would become less accurate, Federal Aviation Administration cutbacks would result in delays and some areas would lose air traffic control services.

By the middle of the century, regular government spending would have to be cut by 95 percent to make Ryan’s budget work, he said.

The massive Medicaid cuts would hurt seniors in nursing homes, poor children and children with disabilities. And the Medicare cuts would force seniors to pay much more.

Obama said the GOP’s argument that this austerity is needed to cut the deficit “might have a shred of credibility were it not for their proposal to spend $4.6 trillion over the next 10 years on lower tax rates.”

Obama noted the GOP is refusing to list a single tax loophole it is willing to close to pay for those tax cuts. There is no way to get close to that level of loopholes without dramatically reducing tax breaks for the middle class, including retirement, health care and home ownership, he said.

Obama also reiterated that he expects the Supreme Court to uphold the health care law, saying that it has not overturned a major economic law affecting commerce since before the New Deal. And he said there are two ways to cover people with pre-existing conditions — either with a single-payer system like Medicare or with an individual mandate.

Republican leaders blasted Obama in turn.

Speaker John Boehner (R-Ohio) said Obama has “recommitted himself to policies that have made our country’s debt crisis worse.” Boehner said Ryan’s budget “makes the tough choices the president refuses to make to address the staggering deficits and debt that are slowing our economic recovery, costing jobs and threatening to destroy the American dream.”

Boehner added, “House Republicans, led by Chairman Ryan, passed a responsible budget that would help put Americans back to work, protect our seniors, close President Obama’s massive budget deficits, and do ‘all of the above’ to address high gas prices. … Republicans are committed to the budget we’ve put forward and committed to solving the serious economic and fiscal challenges our country faces. It’s time for the president to join us.”

Senate Minority Leader Mitch McConnell (R-Ky.) also blasted Obama’s renewed call for the “Buffett Rule,” which would ensure millionaires are paying at least as high a tax rate as the middle class is.

“This is yet another proposal from the White House that won’t create a single job or lower the price at the pump by a penny but may have the opposite effect,” McConnell said in a statement. “Just as with the president’s proposal to raise taxes on American energy manufacturers and increase the cost of energy, this is yet another sign that the White House is out of ideas and is simply focused on tax hike show-votes rather than pushing for the dozens of jobs and energy bills that have passed the House but are stalled in the Democrat-led Senate.”