HERSHEY, Pa. -- With a closely watched party endorsement vote set for this morning, seven of the GOP contenders for U.S. Senate gave their final pitches for support in a forum here Friday evening.

The unwieldy panel -- which included Chester County businessman Steve Welch, Washington County entrepreneur Tim Burns, retired Armstrong County coal company owner Tom Smith, former state Rep. Sam Rohrer of Berks County, Harrisburg attorney Marc Scaringi, Bedford County pharmacist John Kensinger and David Christian, a veteran from Bucks County -- kept that battle civil, directing most of their attacks at Democratic U.S. Sen. Bob Casey and the burdens of Washington regulations.

They called Mr. Casey a robot and a rubber stamp and agreed on the importance of a balanced federal budget. Meanwhile, out in the hallway, Gov. Tom Corbett was buttonholing select committee members to shore up support for his chosen candidate, Mr. Welch.

Gov. Corbett, in a brief interview before he began those private chats, said he believed that Mr. Welch will prevail: "I picked. I believe that the party will follow along."

Party officials and committee members will be choosing whether to select Mr. Welch as the governor has requested, vote to endorse one of his Republican opponents or sit out this morning's party vote entirely.

Some grassroots groups are calling on party members to choose an open primary, arguing that state leaders should educate voters, not pre-select their candidates. Activists from FreedomWorks, Kitchen Table Patriots and other organizations presented a letter outlining that view to GOP Chairman Rob Gleason. He accepted the petitions, though others left in meeting rooms were tossed in the trash, the activists said.

Mr. Gleason said endorsing a candidate, and vetting that contender, is the party faithful's responsibility: "I'm always confident of supporting the governor and his choice. We'll see how things go."

Party activists from across the state said they believe the morning meeting likely will end in an endorsement for the Corbett-backed Mr. Welch, though it may be a lengthy balloting process to reach that decision. Regardless of that vote, most of those candidates are expected to remain in the race.

The U.S. Senate race isn't the weekend's only drama: an afternoon forum featured the two candidates for state auditor general, who also are seeking the party endorsement, trading some sharp retorts over their background and qualifications for the office.

Frank Pinto, a former college professor and president of the state's Association of Community Bankers, labeled state Rep. John Maher, the eight-term Upper St. Clair legislator, as an insider with political baggage, including his votes in support of the 2005 pay raise and the 2001 pension increase. Mr. Maher defended those votes, noting that he never accepted the pay raise and that he didn't take reimbursements for mileage or other expenses until several years ago.

Mr. Maher also called for the auditor general to keep a closer watch over the state's Marcellus Shale well data, noting recent reports that hundreds of wells had not been counted properly.