PROVIDENCE, R.I. (AP) — Democrats swept to victory in the top races of Rhode Island’s election, retaining seats in the U.S. House and Senate and keeping the Rhode Island House speaker’s chair. Voters approved a plan to let the Twin River slot parlor in Lincoln expand into a casino, but local opposition stopped a similar plan at Newport Grand.

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 Republican challenger Michael Riley.

And in a surprise to no one, Rhode Island voters 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 4-to-1.

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 slots parlor.

The Cicilline-Doherty race remained tight until well into the evening Tuesday as votes were tallied. The 1st District includes northern and eastern areas of the state. With 95 percent of precincts reporting early Wednesday, Cicilline had claimed 53 percent of the vote to Doherty’s 41 percent.

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 was a winning argument statewide, as voters approved the two ballot questions by more than 2-to-1 margins. But casino proposals also require local approval, and the local Newport referendum was rejected by 54 percent of city voters.

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 construction project.

Voters also cast ballots in dozens of state legislative races.

In the most highly watched contest, House Speaker Gordon Fox fended off a spirited challenge from independent candidate Mark Binder, who criticized the Democratic speaker’s role in the $75 million loan guarantee given to former Red Sox pitcher Curt Schilling’s failed video game company, 38 Studios.

Tuesday’s election was the first big test of a new state law that requires voters to show identification, such as a driver’s license or passport. This year, they also were also 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.