San Francisco - Were they just to take their cues from television ads, voters in California might think that when they go to the polls on November 4, they are choosing not a national president but only congressional representatives - and a handful of proposals.

That's because the largest US state, with 55 electoral votes in the indirect presidential election system, is such a lock for Democrats that neither Democrat Barack Obama, 47, nor Republican John McCain, 72, have campaigned much there.

That leaves the political airwaves open to proponents and opponents of a constitutional ban on gay marriage, a law protecting pregnant pigs and egg-laying hens, and decriminalization of marijuana.

Around the country, ballot initiatives - or issues put directly to voters - are down from 204 in the last presidential to just 153, according to the progressive Ballot Initiative Strategy Centre.

That might seem surprising given the power of such measures to serve as wedge issues, especially for Republicans, in increasing voter turnout.

But the thinking this year seemed to be that with such monumental issues at stake - recession and war - efforts to sidetrack voters with an avalanche of controversial initiatives could backfire.

"At best, it doesn't move voters, and at worst for Republicans, it moves them against them," party strategist Matthew Dowd told The New York Times. "Not so much on the issue, but it becomes, 'Why are we having a discussion on this issue when we should be talking about things that matter'?"

California's gay marriage issue is especially hard fought after the state supreme court earlier this year dismissed other attempts to ban gay marriage as unconstitutional. That set off a gay marriage frenzy as same sex couples rush to get hitched before election day.

Opponents of gay marriage have pulled ahead 52 to 43 per cent in polling, thanks to an aggressive ad campaign that claims teachers will indoctrinate elementary school students in the delights of gay marriage if the ban fails to pass.

Arizona and Florida also will vote on constitutional amendments to ban same sex marriage. According to the Christian Science Monitor, 27 states already have constitutional amendments banning gay marriage.

California voters also be asked to approve the expansion of drug treatment for criminals, increase the use of renewable energy, decriminalize the possession of small amounts of marijuana and require a waiting period and parental notification for teenagers seeking an abortion.

"These ballot proposals can be bewildering and you really have to study the issues beforehand," said Nana Nasef, a stay-at-home mother in San Francisco. "You go into the voting booth and there is page after page that you have to vote on. I make a list beforehand. Otherwise there is no way to make sense of it."

Access to legal abortions could also be limited in South Dakota with an initiative which would ban abortion except in cases of rape, incest or a threat to the mother's life. A similar measure that did not include the exceptions failed in 2006. In Colorado, pro-life groups are asking voters to amend the state constitution so that legal rights begin "from the moment of fertilization," a proposal that would result in murder charges for violation.

Marijuana legalization initiatives are on the ballot in Massachusetts and Michigan.

Michigan voters also will vote on a proposal to allow embryonic stem cell research, and on a constitutional amendment to permit casino gambling, while in Florida voters will decide on an initiative that would prevent the legislature from banning or restricting illegal aliens from owning property. Massachusetts voters could ban dog racing.

Alcohol initiatives are on the ballot in Missouri, South Dakota and Maryland, where voters will be asked to allow Sunday sales of alcohol.

Proposals to ban affirmative action, used by governments to promote racial and gender equity in use of public funds, will be considered by voters in Arizona, Colorado, Missouri, Nebraska and Oklahoma. Arkansas voters will be asked to ban anyone who isn't married from adopting kids, while in Hawaii voters will consider lowering the minimum age for the office of governor from 30 to 25.

Voters in Obama's home state of Illinois face just one question - whether to convene a state constitutional convention. In contrast, John McCain's home state of Arizona faces the longest list of initiatives with 10 measures. These include proposals to ban gay marriage, reduce regulation of medical insurance, regulate payday loans, crackdown on undocumented immigrants, ban affirmative action and raise the salaries of state legislators.

Given the variety of options, it's not surprising that voters in Arizona will also be asked to make it harder to pass ballot measures - specifically those that would result in higher spending or taxes.

If approved, such measures would have to win the support of a majority of registered voters, not just those who cast a ballot, in order to become law.