By Tony Romeo

PITTSBURGH, Pa. (CBS) — Pennsylvania’s embattled governor went to his home base of Pittsburgh today to formally announce his bid for re-election.

Gov. Tom Corbett addressed his supporters inside a museum in Pittsburgh.   Outside, members of the Pittsburgh Federation of Teachers called out the governor for, in particular, his cuts to education.

“We need somebody with a vision for public education, among other issues,” said the union’s leader, Nina Esposito-Visgitis.

But in his speech to supporters, Corbett said he inherited a deficit of billions of dollars and had to make tough decisions.

“Pennsylvania was spending more than it had,” the governor said.  “We were spending our children’s children’s children’s children’s future. I promised to spend within our means.”

Corbett launches his campaign with some of the lowest poll numbers of any incumbent Pennsylvania chief executive seeking re-election since the state constitution was changed in 1968 to allow governors to serve two terms (see related story).

Eight Democrats have announced bids to challenge him.