(CNN) Two weeks from today, voters in western Pennsylvania will go to the polls to choose their next member of Congress. It might just be the most important race no one is paying attention to right now.
On its face, Pennsylvania's 18th District isn't much of a Democratic target. Donald Trump won the district by 20 points in 2016 and Mitt Romney carried it by 17 in 2012. Republican Rep. Tim Murphy had held it easily since 2002; he was unopposed in 2014 and 2016.
But Murphy was forced out of Congress in October when reports surfaced that he had urged a woman with whom he was having an affair to get an abortion.
That forced this special election. Republicans chose state Rep. Rick Saccone as their nominee, Democrats picked prosecutor and veteran Conor Lamb.
From the start, Republican insiders were worried about the candidate contrast: Saccone is a 60-something-year-old state legislator, Lamb is a 30-something Marine.
That mismatch in candidate quality wouldn't have been enough to turn this into a barn-burner. But when coupled with an unpopular Republican president, the political climate might just be turning toxic on Saccone.
David Wasserman, the House editor at the nonpartisan Cook Political Report, changed the rating on the Pennsylvania race Tuesday from "lean Republican" to "toss-up," writing by way of explanation:
"For over a month, private polls on both sides have shown Saccone leading in the low-to-mid single digits, often within the margin of error. Today, the candidates are better known, but Lamb hasn't let Republicans nationalize the race and Saccone still hasn't pulled away. The contest is exceedingly close, and Republican operatives are preparing to spin a loss as the result of an unfavorable candidate contrast."
It's clear Republicans are on the defensive and are prepping for a loss.
The Point: Republicans can try to spin a loss in Pennsylvania any way they like. But if Democrats win a district that Trump carried by 20 points, the worry coursing through Republican ranks today will rapidly transform into outright panic. And rightly so.
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