Providence — Rhode Island voters re-elected top Democrats on Tuesday in an election marked by long lines, ballot mix-ups and the approval of casino games for the Twin River slot parlor.

In the day's most hotly contested race, U.S. Rep. David Cicilline edged Republican Brendan Doherty to win a bitterly personal contest and secure a second term representing the state's 1st Congressional District.

Democrat Sheldon Whitehouse easily beat back a challenge from Republican Barry Hinckley to win a second term in the U.S. Senate. In the state's 2nd Congressional District, U.S. Rep. Jim Langevin won a seventh term after coasting past GOP challenger Michael Riley.

And in a surprise to no one, Rhode Island voters casting ballots Tuesday overwhelmingly favored the re-election of President Barack Obama over Mitt Romney, the former governor of neighboring Massachusetts. Registered Democrats outnumber registered Republicans in the state nearly four-to-one.

A proposal to bring table games to Twin River passed both locally and statewide — a requirement for casino referendums. But voters in Newport defeated an attempt to bring games like poker and blackjack to the Newport Grand slot parlor.

The Cicilline-Doherty race was the most hotly contested of the year, and remained tight until well into the evening Tuesday as votes were tallied. The 1st District includes northern and eastern areas of the state.

Doherty, the former leader of the state police, hounded Cicilline with questions about his character, accusing the freshman of lying to voters to get elected in 2010 and attacking his work two decades ago as a criminal defense attorney.

Cicilline, who was mayor of Providence for eight years before being elected to Congress two years ago, was harshly criticized for saying during his 2010 campaign that the city's finances were in excellent condition. Within a few months, it was announced the city faced a $110 million deficit.

In the final days of the campaign, national Republicans and Democrats poured hundreds of thousands of dollars into TV attack ads, including one GOP attack tying Cicilline to a child molester and murderer he defended two decades ago.

Cicilline worked to put the race in a national context, arguing that Doherty would advance the Republican agenda in Congress. It was a partisan message that resonated with Cicilline voter Sandra Medina.

"I believe that Democrats work harder for the people," said the 38-year-old East Providence woman. "I believe that he has done and represents Rhode island very well."

Voters in Rhode Island confronted a long list of ballot questions, led by the two casino questions.

The owners of Twin River and Newport Grand had argued that they needed table games to compete with casinos now authorized to be built in Massachusetts.

It proved to be a winning argument statewide, as voters overwhelmingly approved the two ballot questions. But casino proposals also require local approval, and Newport Grand's efforts fell flat in the seaside resort community known for its Gilded Age mansions and upscale tourism.

Lincoln voters enthusiastically supported the Twin River referendum. Officials say the facility could begin offering poker and blackjack as soon as next summer.

Other ballot initiatives will issue bonds for several building projects, including a $94 million veterans home, a $50 million plan to renovate campus buildings at Rhode Island College, a $25 million affordable housing initiative, $20 million for open space and recreational facilities and a $20 million wastewater and drinking water project.

Tuesday's election was the first test of a new state law that requires voters to show identification. This year, they also will be allowed to present non-photo ID, such as a utility bill.

While no major problems with the new law were reported, poll workers dealt with long lines, voting machine problems and, in at least two polling places, ballot mix-ups.

Incorrect ballots were delivered by the state Board of Elections to polling places at the West Kingston Elementary School in South Kingstown and Elks Lodge in West Warwick. Voting was delayed by up to an hour until new ballots were printed and delivered, and some voters left without casting ballots, officials said.

"It was a very unfortunate mix-up with the Board of Elections," Dawn Piers of the South Kingstown Board of Canvassers told The Associated Press. She said voters were asked to return later or told they could cast a provisional ballot at two other locations.

South Kingstown got ballots meant for a precinct in North Kingstown, while West Warwick got some meant for Woonsocket, town officials said.

Forty-five-minute lines greeted voters Tuesday morning at one East Side Providence polling place. Voter Christine Asmus said she thinks the voter ID law and heightened interest in a presidential election year were responsible.

"I think it's taking longer because they're checking IDs," she said. "I've never seen a line like this."