Paul Begala, a Democratic strategist and CNN political commentator, was a political consultant for Bill Clinton's presidential campaign in 1992 and was counselor to Clinton in the White House. He was a consultant to Priorities USA Action, the pro-Hillary Clinton super PAC. The opinions expressed in this commentary are his.

The results from Pennsylvania should send Republicans into a panic. Pennsylvania's 18th Congressional District, which Democrats haven't contested for years and in which Donald Trump won by nearly 20% in 2016, appears poised for a victory by Democrat Conor Lamb in the squeakiest of squeakers. Any time a party improves on its prior performance by 20%, attention must be paid.

One of my political mentors, former Georgia Gov. and US Sen. Zell Miller, taught me "politicians only understand two things: what you can do for them, and what you can do to them." The Pennsylvania special election shows that Trump can do something to the Democratic vote: Put it on steroids, and he can't do much for the Republican candidates. He doesn't provide a lot of air cover.

After Democrat Ralph Northam decisively won the Virginia governor's race, Trump apologists claimed Republican Ed Gillespie didn't run on a Trumpian agenda. (In fact, Gillespie was pilloried for running anti-immigration ads straight out of the Trump playbook). But no one can complain that Republican Rick Saccone was insufficiently pro-Trump. He often described himself as "Trump before Trump was Trump."

Some lessons emerge. First for the Republicans:

Trump can't save you, even in a Trump district. The President did not sink Saccone, but he could not save him. He personally campaigned for Saccone. So did Vice President Mike Pence. And Ivanka Trump, Donald Trump Jr. and Kellyanne Conway. The President touted The President did not sink Saccone, but he could not save him. He personally campaigned for Saccone. So did Vice President Mike Pence. And Ivanka Trump, Donald Trump Jr. and Kellyanne Conway. The President touted his steel tariffs , a popular position in steel country. Unless there's a last-minute surprise in the counting of absentee ballots or a recount, none of it was able to hold even a district Trump had carried in a landslide in the last election.

The GOP tax cut didn't play with blue-collar voters in a red district. Washington Republicans told themselves that their massive $1.5 trillion tax cut would save their congressional majority. Lamb Washington Republicans told themselves that their massive $1.5 trillion tax cut would save their congressional majority. Lamb opposed the Trump tax cut, calling it a "giveaway" to the rich and calling for tax cuts targeted to the middle class. The results in Pennsylvania suggest that working-class voters don't see the tax bill, which was heavily weighted toward corporate tax cuts, as benefiting them.

Money isn't everything. GOP groups pumped $10.7 million into the race. Lamb and Democratic groups did not have enough to match them, but they did GOP groups pumped $10.7 million into the race. Lamb and Democratic groups did not have enough to match them, but they did raise and spend enough to perform exceedingly well: some $2.6 million. Even in a district they have not lost in a generation, Republicans learned that if a Democrat has sufficient funds, they cannot bury him in an avalanche of ads.

Chaos hurts. On Election Day, Trump fired Secretary of State Rex Tillerson. By Twitter. His personal assistant was tossed out of the White House. Rumors flew about firing the secretary of veterans affairs, the national security adviser. Oh, and the On Election Day, Trump fired Secretary of State Rex Tillerson. By Twitter. His personal assistant was tossed out of the White House. Rumors flew about firing the secretary of veterans affairs, the national security adviser. Oh, and the Stormy Daniels storm reached Category 4 proportions. Not the kind of Election Day news that inspires your folks to vote.

There are important lessons for the Democrats, too:

• Democrats need a big tent. There are two kinds of parties, just like there are two kinds of churches: those who hunt down heretics and those who seek out converts. Lamb ran far ahead of Hillary Clinton or Barack Obama because he sought out converts. Rather than denigrate Trump voters, he listened to them, respected them, reached out to them. It was easy for Lamb to do; he fit the district.

Guy Cecil, who runs Priorities USA Action, the mammoth Democratic Super PAC (that I used to advise), wisely notes that Democrats need to "meet voters where they live. We can't run cookie-cutter campaigns." Lamb localized his campaign; Saccone nationalized his.

Democrats have to be for something, not just against Trump. Lamb Lamb ran a campaign based on middle-class economics and middle-class values. He was unabashedly pro-union. He is committed to fighting for Medicare and Social Security. He opposes repealing Obamacare. He called for major investments in job-generating infrastructure projects and a program to allow people to work off their student debt through service.

Democrats have the wind at their back. After sweeping Virginia and New Jersey in 2017, Democrats picked up After sweeping Virginia and New Jersey in 2017, Democrats picked up a US Senate seat in blood-red Alabama . And now Lamb's surprising strength in a district Trump won in a landslide suggests the Democrats can spread the map and run in even the reddest of places.

Dan Sena, executive director of the Democratic Congressional Campaign Committee, told me his committee invested about $1 million in the race but did so quietly, so as not to nationalize the race. "This race demonstrates how we will continue to win elections this year -- by highlighting our candidates with records of service and ensuring they are equipped to tell their stories straight to voters, bolstered by strategic investments from the DCCC," Sena said. "Conor was our best asset in this race, and there are a lot more candidates with stories like his, in even more competitive districts."

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