To pass reforms of Oklahoma's tax structure, Gov. Mary Fallin needs to win support of both House Republicans and Democrats.

It won't be easy.

The state constitution requires that all revenue-raising bills have to pass the Oklahoma Legislature with a three-fourths majority. In the state House, it's 76 votes.

House Republicans came out of the November election with 75 members, but two GOP lawmakers resigned before session began Monday. That means at least three Democrats have to cross the aisle to support cigarette and fuel tax increases, which are expected to raise nearly half a billion dollars if adopted.