Vice President Biden delivered a blistering critique Monday of the House Republican budget plan, kicking off a midterm campaign effort aimed at winning votes by highlighting what Democrats say would be the catastrophic effects of the conservative vision shaped by House Budget Committee Chairman Paul Ryan (R-Wis.).

Biden said the GOP plan, passed this month, would devastate the middle class and eviscerate programs that help the poor while cutting taxes for the rich. The remarks launched what aides described as a months-long effort to attack Republicans on economic policy, in an attempt to reprise a successful 2012 campaign strategy.

“This is not your father’s Republican Party,” Biden said at George Washington University. “What they clearly value, this new Republican Party, is more tax cuts for the wealthy at the expense of the middle class . . . because they genuinely believe in their hearts that that’s the way in which you build a 21st-century economy.”

Biden’s argument comes as Democrats search for a political message that can gain traction ahead of the November elections. While portraying Republicans as out of touch was enormously successful two years ago, Democrats this year face a far more challenging electoral terrain.

“The vice president is lashing out because he has no answer for the question Americans are asking: Where are the jobs?” said Brendan Buck, a spokesman for House Speaker John A. Boehner (R-Ohio), in response to Biden’s remarks Monday. “This administration has overseen the worst economic recovery in our history and has a budget that never balances, ever — and hysterical attacks from Joe Biden won’t change that.”

Biden argued that the Republicans’ budget is inconsistent with the values they espouse.

“They say they value education for our children. They say they agree with us that the best-educated country will seize the day in the 21st century,” the vice president said. “But yet they cut domestic spending by 15 percent below our budget. They won’t say exactly where they’re going to do it, but here’s what across-the-board cuts would be — and that’s what they’ve done in the past.”

Biden’s critique echoes that of the left-leaning Center on Budget Policy and Priorities, which has argued that neither the Ryan nor the Obama budget would adequately fund domestic programs. An analysis by the group this month found that the Ryan budget, compared with Obama’s budget, would pour $1 trillion less into domestic programs by embracing the deep spending cuts known as sequestration and then cutting programs by an additional $800 billion over the next 10 years.

The group has also argued that nearly 70 percent of the Ryan budget’s overall cuts would come from programs that serve people with low or moderate incomes.

Ryan has taken strong exception to the liberal critiques, saying his budget projects $43 trillion in spending over the next 10 years, compared with the $48 trillion the federal government is expected to spend without new legislation. “Nearly $43 trillion is enough,” his office said recently.

The topic of Biden’s speech suggested that he may play something of a “bad cop” to Obama’s “good cop” as the midterm strategy unfolds. White House officials have said that the strongest role Obama can play this summer and fall is to draw contrasts between GOP and Democratic thinking on the economy.

The president has been doing that primarily by noting his own proposals — to raise the minimum wage, for instance, or to promote pay equity for men and women. While he has criticized Republicans, he has mainly focused on what Democrats bring the to the table.

Biden’s sharp focus on the House Republican plan suggests that he will be hitting the GOP harder in hopes of revving up the Democratic base and painting the GOP budget in the darkest light possible.

“House Republicans have a plan to balance the budget and create jobs,” Ryan spokesman William Allison said. “But the administration doesn’t have much to brag about. Now all they’ve got left are baseless attacks and stale rhetoric.”