Pennsylvania Republicans in the U.S. Senate primary are doing what national Republicans did in the presidential race: they're eating each other alive.

The five-way race for the GOP nomination to challenge Sen. Bob Casey in November has effectively become a three-way race among rich young Chester County biz guy Steve Welch, rich older Armstrong County coal guy Tom Smith and former Berks County state legislator Sam Rohrer.

(David Christian of Bucks County and Marc Scaringi of Cumberland County also are on the ballot.)

Welch is party-endorsed and backed by Gov. Corbett. Smith is spending a ton of dough on TV. And Rohrer, who ran in the 2010 primary against Corbett, getting 31 percent of the vote, has lots of grassroots tea party-type support.

So it's the party guy, the money guy and the grassroots guy.

In a very un-GOP-like fight, Welch and Smith are calling each other Democrats (Welch was one and voted for Obama; Smith was one for decades and served in local office as a Democrat) and both tag Rohrer for having voted for the infamous 2005 legislative pay raise.

What's a Republican voter to do?

The mess is due to the fact state party leaders could not find a name candidate to run against Casey and couldn't get a seasoned pol, such as Philly `burbs U.S. Rep. Jim Gerlach, into the race.

Philly voters probably haven't heard much about this battle since, well, there are no GOP Philly voters, and since most politicos believe that unless Casey legally changes his name to, oh, I don't know, Adolf Hilter-Stalin, before the November ballots are set, he's a lock for re-election.

But GOP results on Tuesday will tell something about the direction of the state party and the political clout of Corbett.

With Republican voter-interest all dried up in the wake of Rick Santorum exiting the presidental contest (if he were running, Rohrer would benefit greatly), the question now becomes what does the state GOP want to be?

The choices? An organized party that can pick its candidates and wants younger faces (Welch is 35); a rural but rich party that wants a monied candidate and self-described "old farm boy" and grandfather of eight (Smith still lives on the farm he was raised on); or a grassroot party that wants a candidate who's run statewide before?

Expected low turnout puts this one up for grabs. But if Welch loses it's a loss for Corbett and party leaders -- and a win for political cannibalism.