Barack Obama (search), a state legislator and former civil rights lawyer, won the Democratic primary for the U.S. Senate on Tuesday, crushing six opponents and setting up a high-stakes race with Republican Jack Ryan (search) that could decide control of the Senate.

Obama, 42, aiming to become only the third black U.S. senator since Reconstruction, rolled up big margins in Chicago and the Cook County suburbs, trouncing his nearest rival, state Comptroller Dan Hynes (search), who had pinned his hopes on help from his father and other powerful Chicago ward leaders.

Ryan, a millionaire investment banker-turned-teacher who had been dogged in the final weeks of the campaign by questions about sealed records of his divorce from actress Jeri Ryan (search), pulled out a victory over seven Republican rivals while largely funding his own campaign.

With 84 percent of precincts reporting, Ryan led the Republicans with 36 percent, followed by dairy owner James Oberweis (search) with 23 percent and state Sen. Steve Rauschenberger (search) with 20 percent.

"In a field of eight great candidates this is a huge victory," Ryan said in his victory speech. "It shows that the Republican party is back and we're unified, we're ready for the general (election) and we will win in November."

Obama had 55 percent of the Democratic vote, followed by Hynes with 23 percent, with 84 percent of precincts reporting.

"I think it's fair to say the conventional wisdom was we could not win," Obama told a cheering crowd of supporters. "We didn't have enough money. We didn't have enough organization. There was no way that a skinny guy from the South Side with a funny name like Barack Obama could ever win a statewide race. Sixteen months later we are here."

Hynes pledged to support Obama in the November election, saying: "He's an unbelievably talented individual, and I respect him very much."

The primary determines the candidates who will vie to succeed GOP Sen. Peter Fitzgerald, who is retiring after one term. National party leaders view the election as a key race in determining who will control the Senate, now narrowly divided with 51 Republicans, 48 Democrats and one independent who leans Democratic.

Obama, a Harvard-trained lawyer whose father was a government official in Kenya, poked fun at his own unusual ballot name while boasting that he had successfully pushed programs to provide health care for needy youngsters through the state Senate.

In the closing days of the campaign, his television ads featured an endorsement from Sheila Simon, the daughter of the late Sen. Paul Simon, D-Ill., one of the state's most popular political leaders. In the ads, she describes Obama as "cut from that same cloth" as her father.

The Rev. Jesse Jackson spoke to Obama supporters at a victory party for the candidate, saying: "At a time when there is so much polarization, so much bitterness and anger and hurt, we need coalition leaders, we need open doors, we need hope."

The candidates — seven of whom are millionaires — largely stayed away from attack ads and focused on issues ranging from health care to immigration, but they grumbled that such issues had little impact.

"If you didn't have a glitzy sex life and you weren't using drugs, you couldn't get covered," said candidate Maria Pappas, the Cook County treasurer. "It's overshadowed everything."

Political newcomer Blair Hull, a former securities trader, pumped more than $29 million into his campaign and took an early lead ahead of the primary, only to sink after unsealed divorce records showed he struck an ex-wife on the leg and allegedly threatened her. Hull also was among a number of candidates, including Obama, who disclosed they had used illegal drugs in the past.

Other Democratic candidates were former Chicago school board president Gery Chico, talk show personality Nancy Skinner and health care executive Joyce Washington.

Other Republicans were business executive Andy McKenna, retired Air Force Gen. John Borling, business executive Chirinjeev Kathuria, former state Rep. Jonathan Wright and Republican retiree Norm Hill.

In the final days of the campaign, Republican leaders declared their concern that Ryan's divorce records contained information that could damage him in a general election, but Ryan maintained the records pertain to child custody and are sealed to protect his 9-year-old son.

Tuesday morning on Chicago's South Side, Ryan voter Kim Snoddy, 40, said she didn't think his choice not to release his divorce records would hurt him.

"I think to counter what happened with Hull they (Ryan's opponents) may be pushing the issue to make him look bad," Snoddy said.

At the same Hyde Park precinct, 32-year-old social worker Marcus Buckley voted for Obama and said he hoped the general election in November would restore Democrats to power.

"The Republicans keep cutting our service funding, and I hope to get a Democratic Congress in control so we can get some money back," Buckley said.