By Tony Romeo

NORRISTOWN, Pa. (CBS) — Montgomery County commissioner Bruce Castor says he is mulling a possible Republican primary challenge to Governor Tom Corbett.

“I believe the Republican party in Pennsylvania has gotten away from understanding that the party is its members — the voters who are registered Republican — and not a handful of people who pick the candidates,” Castor told KYW Newsradio today.  “It seems to me we tend to lose elections when we hand-pick our candidates; we tend to win elections when we have primaries and produce strong candidates that are supported by our base.”

Franklin and Marshall College political analyst Terry Madonna says if Castor — a former Montgomery County DA — decides to run, it’ll be a big deal.

“(It would be), without doubt, one of the more serious — if not the most serious — challenge to an incumbent governor seeking renomination in modern history,” Madonna tells KYW Newsradio.

Madonna says that in Pennsylvania, incumbent governors tend to not face strong challenges from the opposing party, let alone their own party.

Castor, meanwhile, says he’s eyeing the race because of what he believes to be Corbett’s lackluster performance.

“I believe the governor is having difficulty living up to the promise that he brought into office with him, largely because his leadership style in dealing with the legislature is not producing results,” Castor says.

And Castor, 51, says he expects to decide on a run by spring.

“Right now I’m lining up donors, strategists, and grassroots organizers,” he said today, “and today’s announcement will enable me to gauge the support I might have for a run.”

Corbett has not announced his re-election bid but has said he does “not intend to break the tradition” of incumbent governors seeking a second term.

Castor lost the 2004 GOP nomination for state attorney general to Corbett by more than five percentage points.

KYW’s Ian Bush contributed to this report.