HARRISBURG, Pa. (AP) — Pennsylvania Senate Democrats on Tuesday challenged Gov. Tom Corbett’s top budget adviser over the necessity of carrying out the administration’s proposed pension fund changes and to explain how it developed an analysis that a Medicaid expansion would cost state taxpayers billions of dollars.

Corbett’s budget secretary, Charles Zogby, gamely answered questions for nearly 2 1/2 hours during the Senate’s first Appropriations Committee hearing of 2013 as lawmakers begin to pick apart the Republican governor’s spending plan.