Marijuana activists in the State of California are rushing ahead with pot-legalization measures to be placed on the 2010 ballot, setting the stage for a confrontation with the federal government’s laws criminalizing marijuana.

California already is home to a thriving medical marijuana marketplace with scores of storefront dispensaries, selling pot to customers with a doctor’s prescription.

Marijuana decriminalization advocates sense the time is ripe to push for pot legalization, when the financially beleaguered state is desperate for new sources of tax revenue.

However legalizing pot for casual users on a city-by-city basis in California, would certainly create conflicts with federal law making marijuana illegal. But it’s unclear how far the federal government would go to impede a state law legalizing small amounts of pot for personal use.

Federal agencies tasked with enforcing the law, are only concerned with pursuing large-scale drug trafficking. It’s unlikely the DEA would institute a crackdown of small-time casual users.

Additionally, the Obama administration under Attorney General Eric Holder, called a federal truce on raiding state marijuana dispensaries that were in compliance with state laws, allowing the storefront shops to operate without federal interference.

DEA spokeswoman Dawn Dearden said, “Marijuana is illegal under federal law and DEA will continue to attack large-scale drug trafficking organizations at every level.” And President Obama has made clear he does not support the legalization of marijuana.

But the White House is also is reevaluating its drug policies to emphasize prevention and treatment, rather than incarceration.

The federal government has few options available to it for clamping down on a state law legalizing pot, since local law enforcement are largely responsible for making arrests. And the federal government can’t force state law enforcement forces to help DEA agents make arrests.

The only true weapon in the federal arsenal would be to withhold federal funding to California and other states legalizing marijuana.

If any of the ballot measures pass, California would be the first state to legalize marijuana for casual use.