CHICAGO, Illinois (CNN) - Illinois Treasurer Alexi Giannoulias on Tuesday night emerged as the Democratic Party's choice to fight for President Barack Obama's former Senate seat.
Giannoulias will now take on moderate five-term Republican Rep. Mark Kirk in the November mid-term elections. Kirk won the GOP primary handily Tuesday night.
Political analysts have said it might be an uphill climb for the Democrats to hold onto the seat that Obama vacated when he became president last year.
Giannoulias' opponent, former Chicago inspector general David Hoffman, conceded in a phone call to him about 10:40 p.m.
Tuesday's primaries included competitive races in both parties for senatorial, gubernatorial and several congressional seats. There were also contests for attorney general, secretary of state, comptroller and treasurer.
But most of the attention focused on the Senate race.
Incumbent Sen. Roland Burris did not run; he was touched by the scandal that led to the impeachment of Illinois Governor Rod Blagojevich.
Republicans are hopeful Kirk will capture the seat.
"Kirk is a moderate. He certainly would appeal to independent and suburban voters," said Russ Stewart, a long-time Illinois political analyst and columnist.
"The people who were energized for Obama are disillusioned and disgusted right now. The Democrats are disillusioned with the Democratic hierarchy that runs Illinois, so a lot of people say, 'I'm going to vote Republican just as a protest as they did for Scott Brown.' " Brown is the Republican who was elected last month in heavily Democratic Massachusetts to fill the late Ted Kennedy's Senate seat.
Giannoulias was the front-runner with more name recognition. He was attacked by Hoffman over controversies relating to a bank owned by Giannoulias' family.
Both candidates tried to convince voters they would run stronger against Kirk in the general election, and each emphasized his independent credentials.
Kirk is highlighting his moderate social record and conservative fiscal credentials as he tries to appeal to Republican primary voters and the broader electorate for the general election.
"I think people are very worried about out-of-control spending in Washington. Trillion dollar deficits as far as the eye can see," Kirk told CNN.
Kirk so far has not won the support of the more conservative elements of his party, including some Tea Party activists in the state.