Although there is still a primary left for him to win, Democratic U.S. Rep.-elect Conor Lamb’s big special election victory last week is boosting expectations for his anticipated matchup against Republican U.S. Rep. Keith Rothfus in the new 17th Congressional District general election.

The respected Cook Political Report changed its rating for Rothfus’ seat from "Leans Republican” to “Tossup” with the congressional map shifting from the current 12th Congressional District, which Rothfus has represented since 2013, to the new 17th District.

Rothfus’ 12th District has stretched from southern Lawrence County and Beaver County eastward to past Johnstown, but the new 17th District would be more compact, covering Beaver County, part of Cranberry Township, and the northern and western parts of Allegheny County.

Of the Allegheny County precincts that were in the 18th District and will also be in the new 17th District, Lamb, a Mount Lebanon resident, won 61 percent of them Tuesday against Republican state Rep. Rick Saccone.

The new congressional maps are, of course, still being contested by Republicans in two separate appeals, one before the U.S. Supreme Court and one before the U.S. District Court in Harrisburg. There were no decisions released as of Friday, and Tuesday is the deadline for potential candidates to file nominating petitions to get their names on the May 15 primary ballot.

With the change in actual geography for Rothfus, a Sewickley resident, comes just as dramatic a shift in the political landscape. The current 12th District voted for President Donald Trump in 2016 by about 20 percentage points while the newly configured 17th District would have gone to Trump by about 3 percentage points.

On Friday, CNN’s Terence Burlij and Eric Bradner moved the 17th District race from “Leans Republican” to “Tossup” following Lamb’s apparent victory, which could still be contested by Saccone.

“The dust hasn’t settled from Tuesday’s special election, but regardless of the result, it shows Democratic strength in southwestern Pennsylvania,” the pair wrote.

“This newly drawn district is a much more competitive seat for GOP Rep. Keith Rothfus to defend,” the CNN analysts said, predicting a race featuring Lamb “will be one of the most closely watched contests come November.”

A third political handicapper, Kyle Kondik, managing editor of Larry Sabato’s Crystal Ball at the University of Virginia’s Center for Politics, kept the outlook for the 17th District at a “Tossup” after moving it from “Leans Republican” last week.

One of the few prognosticators to even acknowledge that Lamb has a primary to still win, Kondik nonetheless said a Lamb vs. Rothfus general election “should be very competitive” while adding that “Lamb eventually might have an advantage given his strong performance Tuesday and the overall environment.”

Next up for Lamb is the Beaver County Democratic Committee endorsement vote Thursday evening at the Monaca Turners Club in Center Township. So far, the candidates vying for the endorsement are Lamb, Sewickley attorney Beth Tarasi and University of Pittsburgh doctoral student Aaron Anthony of Shaler Township.

Other Democratic primary candidates include consultant and local Democratic activist Ray Linsenmayer of McCandless Township and Erin McClelland of Harrison Township, who lost to Rothfus in the 2014 and 2016 general elections.