Maryland voters could become the first in the nation to decide by popular vote to allow illegal immigrants to pay in-state tuition at public colleges.

The ballot question is one of several high-profile ballot measures before voters on Tuesday. Students would have to attend a Maryland high school for three years, and they or their parents would have to show they filed state income tax returns to qualify.

Maryland voters also will decide whether to expand gambling to include table games like blackjack and a casino near the Nation's Capital. They'll be voting after being bombarded by more than $80 million in advertisements.

Voters also will be deciding whether to allow same-sex marriage. The state's congressional redistricting map also has been petitioned to the ballot. 

Maryland residents will decide whether to legalize same-sex marriage, a decision that could have far-reaching implications.

Gov. Martin O'Malley had signed gay marriage into law in March, but opponents collected enough signatures to force a ballot referendum in Tuesday's election.

The vote carries weighty consequences, especially because gay marriage has never succeeded at the ballot box. Thirty-two states have held votes on same-sex marriage since 1998, and all 32 have opposed it.

Maryland is one of four states with referendums on the issue Tuesday. The others are Maine, Washington and Minnesota.

O'Malley, who strongly supported the law, has said it protects the religious beliefs of clergymen who oppose same-sex marriage. But it's proved a tough sell among some black clergy and their congregations.