Nassau's formidable Republican Party fielded some Election Day setbacks after dropping the hotly contested district attorney race and facing a possible upset in the Oyster Bay supervisor race.

Democrat Madeline Singas overwhelmingly won the DA job over former Hempstead Supervisor Kate Murray with 58 percent of the vote. Singas had been acting DA since Kathleen Rice was elected to Congress.

In Oyster Bay, where Democrats do not hold a single seat on the town board, Democratic challenger John Mangelli declared victory with an advantage of less than 100 votes. Incumbent John Venditto says the election was too close to call.

It's likely to be weeks before an official winner is declared in Oyster Bay as absentee ballots are counted, but analysts attribute the tight race to the federal corruption probe at Town Hall.

"Whether you did anything or you didn't... that doesn't really matter. As the captain of the ship, you're going to be responsible for everything that happens on that ship," said political strategist Mike Dawidziak.

Singas, meanwhile, told News 12 that fighting political corruption will be high on her agenda. "I feel the taxpayer dollar needs to be protected. We have to get to the bottom of pay-to-play politics in the county," said Singas.