In addition to selecting the U.S. president, voters in 34 states will make decisions on a wide range of ballot issues Tuesday.

One that could have an immediate impact is on the ballot in Colorado. Like most states, Colorado now gives its top-polling presidential candidate all its electoral voters, in this case, nine of them. The candidate who wins 270 electoral votes across the United States will win the election.

Only Maine and Nebraska can now split their electoral votes. If the Colorado measure wins, Colorado would split its electoral vote to match the popular vote in the state. The change would become effective immediately and could conceivably shift the balance in this election. So far, however, the measure is trailing in voter surveys.

A California measure called Proposition 71 would provide three billion dollars in state funding for stem cell research.

The actor Michael J. Fox appears on television commercials supporting the measure. The actor suffers from the nerve condition Parkinson's disease, and says the research offers hope to people like him.

"My most important role lately is as an advocate for patients, and for finding new cures for diseases. That's why I'm asking you to vote yes on Proposition 71, the stem cell research initiative," he said.

The measure's opponents, including actor Mel Gibson, say it permits the harvesting of stem cells from human embryos, destroying them. Other critics question the cost of the measure, which will total six billion dollars over 30 years, including interest.

In Arizona, a controversial measure called Proposition 200 would force state residents to prove they are citizens before they register to vote, which is not currently required, and would also make local officials report illegal immigrants who apply for government services.

Most Arizona politicians oppose the measure, as does the state chamber of commerce, but it leads in the polls heading into the election. Arizona governor Janet Napolitano also opposes it, but says Arizonans are frustrated with illegal immigration and what it costs the state.

"It's obviously something that the next president of the United States has to deal with. Arizona and the other border states are paying a terrific price for the failure to deal with immigration reform," she said.

Oregon is one of 11 states with measures on the ballot to ban gay marriage, following efforts in several communities around the United States to extend marriage rights to same-sex couples. Supporters of the measure worry about the erosion of traditional institutions. Opponents say it unfairly discriminates against gays and lesbians.

More than 160 state measures are on ballots around the country. California leads the nation with 16.

Political scientist Robert Eisinger of Lewis and Clark College in Portland, Oregon, says they complicate the ballot. "And as a result, it requires a lot of work on the part of a citizen to inform himself or herself. It is very difficult to wake up at 6:30 in the morning, go to work, commute, punch a clock, put in a good day's work, go home, perhaps feed the kids, and then learn about the intricacies associated with public policy," he said.

But he says people in Oregon, California, and 32 other states want a direct voice on the issues, despite the demands that it places on them as voters.