Don't federal laws make it difficult for a state to protect medical marijuana patients?

Since shortly after the World Trade Center attack, the U.S. Drug Enforcement Administration (DEA) has selectively conducted raids on medical marijuana dispensaries and grow operations in California, where medical marijuana has been legal since 1996.  During his campaign, President-elect Barack Obama indicated on several occasions that raids in states which recognize medical marijuana would not continue in an Obama administration.

Even under President Bush, who vigorously opposes medical marijuana, DEA interference has not been a significant problem in states with tightly crafted medical marijuana laws (such as our neighbor states Vermont and Maine), . Since 99% of marijuana arrests nationwide are made by state and local law enforcement, the bill being proposed in New Hampshire would provide seriously ill patients with a strong degree of protection against arrest and criminal prosecution.