Lamb took to the role, positioning himself as a centrist even as national Republican forces descended on the district to fill airwaves and social media with depictions of the first-time candidate as little more than a lemming for Nancy Pelosi - the California Democrat, House minority leader and GOP punching bag.
Lamb mostly avoids Trump, who remains generally popular in the district, even if slightly diminished from his Election Day dominance.
Not only did the president campaign for Moore, tweet for Moore - but Trump essentially saved Moore's campaign after numerous and detailed sexual assault allegations were leveled against the Republican candidate.
The candidates - Democrat Conor Lamb and Republican Rick Saccone - are in a tough fight in which outside groups have spent over $12 million. And he embraces unions, highlighting Saccone's anti-labor record at the statehouse - a noticeable deviation from Murphy's status as a union-friendly Republican.
That 20-point margin Trump won the district by in 2016 gives us a baseline of Trump support in the district.
"They're all watching", President Donald Trump told a Pennsylvania crowd on Saturday ahead of Tuesday's hotly contested House special election taking place in a district that he won by almost 20 points in 2016.
"Just because my father's not on the ticket, they have to show up and vote", Trump Jr. said according to the Tribune Review.
Meanwhile, Democrats' opted for a 33-year-old Marine veteran and former federal prosecutor who hails from a well-established political family in Allegheny County. He has run a campaign ad with a picture of him shooting what appears to be an AR-15. But it also would add to four close-but-no-cigar upset bids in special House elections a year ago.
The legal battle over Pennsylvania's congressional boundaries has led to a new map sketching out the state's 18 U.S. House districts.
Outside his office in Mount Lebanon, Pennsylvania, Democratic State Rep. Dan Miller told me "Conor [Lamb] is from right here - in fact, he lives in his grandparents' home right down the street".
Registered Republican Brett Gelb voted for Saccone, largely because the Republican candidate promised to support the president.
This election is the first chance both sides have to gauge how their party will do in the first midterm elections of Trump's presidency. Jobs and wages up. Greene questioned. "Rick Saccone has walked the walk".
Voters in Western Pennsylvania head to the polls Tuesday to pick a new congressman.
Trump won the Pennsylvania district by 20 points in 2016, and Republican Mitt Romney won it by 17 points in 2012.
Nation-wide focus on the district began with Rep. Tim Murphy's (R-Upper St. Clair) resignation after the Pittsburgh Post-Gazette reported that he asked a woman he was having an affair with to get an abortion, despite his anti-abortion policies. He resigned last fall.
But the region has doesn't have as many steelworkers as it did in the industry's heydays, even if there's still a cultural association.
"Mr. Lamb has done what many Democrats have been unwilling or unable to do: speak directly and plainly to voters about their concerns".
That's one reason many consider the special election as a potential sign of things to come.
Polls in the district are open from 7 a.m.to 8 p.m. EDT. President Trump handily beat out Democratic presidential nominee Hillary Clinton in the 18th district back in 2016 on his way to capturing the Keystone State and subsequently the White House.
Even if Saccone, a state legislator, prevails, it would demonstrate that Democrats are competitive in places they hadn't been before and force the GOP to spend time and money defending what had been safe Congressional seats as they try to hold on to their House majority in November.
Some Republican operatives, speaking on condition of anonymity, have been laying part of the blame on Saccone's skills as a campaigner.
The victor replaces Republican Tim Murphy, who resigned in October amid a sex scandal.