(Pablo Martinez Monsivais/AP Photo)

MINNEAPOLIS-President Obama says he's been itching to "say what's on my mind" about Republicans in Washington. And today on the banks of Lake Harriet he let loose, turning an official event on the economy into a rally for Democrats in the midterm campaign.

"So far this year Republicans in Congress have blocked or voted down every single idea to strengthen the middle class," Obama told a crowd of 3,500.

"Don't boo," he quipped. "I want you to vote."

Obama accused Republicans of deliberate inaction, of being "tone deaf," focusing more on elections and "media sound bites" than progress.

"They don't do anything except block me. And call me names," Obama said. "It can't be that much fun. It'd be so much more fun if they said let's do something together."

While not mentioning him by name, the president came out swinging at House Speaker John Boehner and a planned GOP lawsuit over executive actions.

He said the suit is a "stunt."

"They're not doing anything and then they're mad that I'm doing something," Obama said. "Now they're going to sue me for doing my job."

"I might have said in the heat of the moment in one of these debates, 'I want to raise the minimum wage, so sue me when I do.' … But I didn't think they were going to take us literally."

A spokesman for Boehner dismissed Obama's suggestion that the lawsuit the House intends to file against the president is a "stunt." "The American people, their elected representatives, and the Supreme Court have all expressed serious concerns about the president's failure to follow the Constitution," said Michael Steel. "Dismissing them with words like, 'smidgen' or 'stunt' only reinforces their frustration."

Obama today called on Republicans to work with him on issues like immigration and "share the credit." GOP leaders have shown little interest in advancing an immigration reform bill this year ahead of the election.

A spokesman for Senate Minority Leader Mitch McConnell said there are areas of bipartisan agreement - such as repeal of a medical device tax and approval of the Keystone XL pipeline - which are "blocked" by Democrats.