Taking an enemy-of-my-enemy approach, two challengers to Senator Arlen Specter of Pennsylvania plan to get together Wednesday night for a public forum on health care.

Representative Joe Sestak, a Democrat who is challenging Mr. Specter in the Senate primary next spring, invited former Representative Pat Toomey, the likely Republican nominee for the Specter seat, to a town-hall-style meeting. They sealed the deal via Twitter.

The event will be held on Mr. Toomey’s home turf in Allentown, at Muhlenberg College. Mr. Specter was not invited.

Christopher Borick, a political scientist at the college who is set to moderate the forum, said both challengers hoped to gain media attention after a summer in which Mr. Specter captured most of it.

Mr. Toomey, who has no serious opposition in the Republican primary, has been somewhat on the sidelines — even though it was his strong standing in the opinion polls that prompted Mr. Specter to switch parties in April and become a Democrat.

Mr. Specter has been all over the state holding meetings where constituent anger at President Obama’s health care overhaul has boiled over.

Mr. Sestak and Mr. Toomey stand at opposite ends of the political spectrum on most things, including health care. Following their party lines, Mr. Sestak favors a government-run health insurance program while Mr. Toomey favors tax incentives to help people buy private insurance.

Mr. Borick said that all 400 tickets to the event had quickly been distributed. Half were divided equally between the two campaigns, with 100 going to students at the college and the remaining 100 to the general public.

He also said he hoped to keep things under control by making sure questions were directed at both candidates. Mr. Toomey represented the area in Congress, although the Lehigh Valley is considered a swing district politically.

Taking a cue from President Obama, the two candidates plan to have a beer together after the 90-minute forum. Perhaps they will plot further strategies against their shared opponent.

Copyright 2009 The New York Times Company