PHILADELPHIA -- President Obama urged Republicans to embrace his forthcoming budget proposal Thursday night by saying that his plan would contribute to the nation's ongoing economic recovery.

The White House budget plan set for release next week is expected to cost $74 billion more in discretionary investments than is currently allowed by spending caps mandated by Congress four years ago in an attempt to reduce the federal deficit. The proposal, a 7 percent increase over levels set by what's known as "sequestration," includes $530 billion on the non-defense discretionary side, an increase of $37 billion over the spending caps; and $561 billion in defense spending, an increase of $38 billion over the spending caps, according to White House officials.

The plan is expected to be dismissed almost immediately by congressional Republicans, who are opposed to new taxes and big budget deficits.

But House Democrats meeting here at a downtown hotel for two days of closed-door planning sessions fully embraced Obama's plan Thursday, saying that increased investment at domestic agencies can help spur private sector growth and job creation. Democrats cast the plan Thursday as key to reviving the economic condition of working- and middle-class Americans, key constituencies that they hope will turn out in droves for the 2016 elections.

In a dinnertime address, Obama said that his plan smartly reverses sequestration, which "doesn’t differentiate between smart government spending and dumb government spending."

Obama seemed to relish the recent Republican focus on income inequality. "Even though their policies have not caught up with it, their rhetoric is starting to sound pretty Democratic," he said.

He even took a subtle dig at his 2012 campaign rival, Mitt Romney, who said in a recent speech that he believes that poverty should be a central theme of the next presidential campaign.

Obama brought it up by noting that one of his former opponents is "Suddenly, deeply concerned about poverty. That's great! Let's go!"

"What we know is middle class economics works," he added. "That’s been the history of this country. That’s been the history of the last six years when we’ve implemented middle class economics and the other side was telling us this would be a disaster … none of that happened."

The president used his brief remarks to revive the spirits of House Democrats, who saw their numbers drop to a historic 188-member low after the midterm elections.

"It is our obligation to make sure that we are crystal clear about what we stand for and who we are fighting for," he told them. "We were all disappointed with the outcome with the last election, and there are a lot of reasons for it and I’m happy to take on some of the blame."

In a campaign-style crescendo toward the end of his speech, Obama implored his colleagues "to stand up and go on offensive and not be defensive about what we believe in."

"I promise you I’m not going out the last three years sitting on the sidelines," he added. "I’m going to be out there making the case every single day."

Obama was at ease in front of one of the friendliest crowds he addresses each year. He began with a reference to Sunday's Super Bowl by urging Democrats to keep the trash talking amongst themselves to a minimum: "I want y’all to keep it clean. I am not taking sides on that one," he said.

And he praised House Minority Leader Nancy Pelosi (D-Calif.), who joined him this past week in a whirlwind trip to India and Saudi Arabia for meetings with government and business leaders.

He called Pelosi "someone who somehow can travel for 17 hours, come off the plane -- perfectly coiffed not a wrinkle on her -- happy as a clam, come back another 17 hours later after two and a half, three days of programs and go straight to a retreat of her caucus -- and never miss a beat. I don’t know what she drinks along with that chocolate. But I want some of it."