American voters are busy weighing local issues this weekend to decide their positions on many state ballot measures, as they prepare to vote Tuesday in the presidential election.

There are a total of 143 ballot measures collectively in 36 states this year, including 84 legislative referenda and 59 citizen initiatives, according to the National Conference of State Legislatures (NCSL), a non-governmental organization which provides information about state legislatures across the country.

US Democratic presidential nominee Senator Barack Obama shakes hands at a campaign rally in Des Moines, Iowa, October 31, 2008. [Xinhua/Reuters]

For many voters, it would certainly be more difficult to decide yes or no over a long list of controversial local issues than to choose either the first African American President or the first female vice president in US history.

Although there is no overriding theme this year, social, energy and environmental issues are mostly among those that voters will face in the voting booth, political observers said.

US Republican presidential nominee Senator John McCain is greeted by supporters as he arrives at a campaign stop in Steubenville, Ohio October 31, 2008. [Xinhua/Reuters]

In California, two controversial initiatives of the 12 state measures are drawing widespread attention.

Proposition 8 demands to amend the state's constitution to specify that only marriage between a man and a woman is legal in California. It was proposed to overturn a ruling by the state Supreme Court earlier this year to legalize same-sex marriage.