BOSTON -- Massachusetts' new Sen.-elect Scott Brown hasn't even started his new job in Washington yet, but his election has already begun to force President Barack Obama and Democratic colleagues on Capitol Hill to go on the offensive.

Brown is expected to be sworn in this week, as soon as last week's election win is certified and the vice president is available to administer the oath of office.

Senate Democrats have already said they will wait for Brown to be seated before revisiting the controversial Obama health care reform bill. Voter anger over that legislation and other big spending bills is largely believed to be what prompted voters, many of them independents, to opt for Brown.

Obama is planning to use his first State of the Union address Wednesday night to respond to the voter outrage that cost his party a filibuster-proof majority in the Senate.

"I think people are angry in this country. They were angry in Massachusetts that we haven't made more progress on the economy," White House Press Secretary Robert Gibbs said.

"We see it all over the country, in tea parties and town halls. People are alarmed and angry about the spending, the debt, the government takeovers," said GOP Sen. Jim Demint of South Carolina.

As for the state senate seat that Brown will be vacating, the only formal session planned for this week is on Thursday and it is unclear whether Brown will attend. No date has been set for a special election to fill the seat.