ST. PAUL - A group advocating the legalization of medical marijuana has launched a $100,000 ad campaign in Minnesota, asking Gov. Tim Pawlenty to open up to legalization.

A new TV ad features a woman suffering from extreme back pain tearfully asking Pawlenty not to stand in the way of a medical marijuana bill.

The Washington-based Marijuana Policy Project says it's spending more than $100,000 to air the message statewide starting later this week.

Last year, the Minnesota Senate approved a medical marijuana bill that would make Minnesota the 13th state to allow medical use of the drug. SF 345, which is sponsored in the House by Rep. Thomas Huntley (DFL-Duluth), passed the House Ways and Means Committee 13-4 on April 9.

The bill is headed for a full House vote, but Pawlenty remains its largest obstacle, standing firm with law enforcement in opposing the bill.

The woman in the ad, Lynn Rubenstein Nicholson of Minneapolis, says she's tired of being a criminal, using marijuana to ease her pain.

Nicholson says she broke her back as a child and currently can't use marijuana because she is required to take drug tests as a condition of receiving other pain medications.