U.S. Rep. Lou Barletta vs. Sen. Bob Casey could well make Pennsylvania ground zero next year in a national referendum on President Trump.

Barletta and Trump are that closely aligned.

Barletta was among the earliest members of Congress to endorse Trump, was a top Pennsylvania campaign surrogate, served on Trump's transition team, and nearly nabbed a cabinet post.

(He wanted Transportation, was asked about Labor, but withdrew from consideration.)

And Mother Jones magazine labels Barletta “Trump’s political godfather.”

That's because when Barletta was mayor of Hazleton (Luzerne County) in 2006, he pushed tough anti-immigration ordinances (later struck down by federal courts) seen by some as the metaphorical first bricks of Trump's "great wall."

Hey, every movement starts somewhere.

Also, according to a source close to Barletta, Trump recently met with Barletta in the White House to encourage him to run for the Senate.

(I'd note one more pro-Trump Republican could come in handy for Trump's agenda. I'm thinking of that Senate health care vote that failed by one vote.)

So, a 2018 race featuring a staunch Trump critic and the state's legacy Democrat — son of a two-term governor, slayer of Rick Santorum, twice-elected U.S. senator — vs, "Trump's political godfather" just might draw attention.

The Associated Press on Monday reported Barletta told GOP officials and others he's in the race. Barletta hasn't confirmed that.

But let's say it's on.

First blush suggests, wait, so what if Barletta's aligned with Trump? Trump's self-immolating. By next year, he won't be stumping for Senate candidates. He'll be suffering the fires of impeachment proceedings.

And, even if he isn't, what about that midterm elections pattern where the party in the White House loses, not gains, seats in Congress?

Plus, Casey's far less inert today than when he entered elective politics. He's a pro-life, pro-gun, pro-labor Democrat in a state where that's a pretty good mix.

And if Barletta's counting on undying loyalty based on early backing of Trump, just think of another member of Congress early on Trump's wagon. Thinking of Jeff Sessions? Work well for him?

Then again, what if newly arrived White House Chief of Staff John Kelly gets Trump off Twitter and on track, and the umpteen probes into Russia, finances, and whatnot never pan out?

What if by next year the mood of the country's mostly settled down but still interested in moving from the politics of the past to whatever you call what we have now?

Barletta's already been lucky once. After being elected to the House in 2010, his congressional district was gerrymandered into what, for almost any Republican, can be a lifelong seat.

The 11th District runs diagonally from northeast Pennsylvania (one county from the New York border) to south-central Pennsylvania (one county from the Maryland border), conveniently skirting Democratic cities of Harrisburg and Wilkes-Barre.

Barletta won in 2010 with 54 percent of the vote. He won his last two re-elections, with 64 percent and 66 percent, respectively.

So, one might wonder, why give up a sure thing for uncertainty?

The argument is that Trump still has lots of support among Pennsylvania Republicans and others who voted for him in 2016, according to insider polls.

"There's no buyer remorse yet," one GOP consultant says.

Barletta can cut into Casey's northeastern home base. And Casey's more left-of-center than when first elected in 2006.

Others looking to take Casey on include a couple of Western Pennsylvania State House members and a few biz types. Barletta's the biggest name so far mentioned.

But Barletta's taken a swing at the big leagues before. Had a tryout with the Cincinnati Reds as an outfielder; didn't make it. By his own admission, he couldn't hit the curve.

Big League politics throws lots of curves.