Thanks to strong backing from organized labor and an agenda that focused heavily on shielding Social Security, Medicare, and Medicaid from GOP attacks, Democrat Conor Lamb on Wednesday was finally declared the apparent winner of the closely-watched special election in Pennsylvania's 18th congressional district—where President Donald Trump won by 20 points in 2016.

"Lamb's victory is a repudiation of Donald Trump and Paul Ryan's plans to gut the American people's earned benefits."

—Alex Lawson, Social Security Works

"Tonight's results demonstrate that when Democrats run on protecting and expanding Social Security and Medicare, they win," Alex Lawson, executive director of Social Security Works, declared in a statement early Wednesday, before the race was called by NBC News. "Lamb's victory is a repudiation of Donald Trump and Paul Ryan's plans to gut the American people's earned benefits."

Running against the fervently anti-union Republican state Rep. Rick Saccone—who has in the past voted for so-called "right to work" legislation—Lamb also placed the right of workers to bargain collectively and protection of worker pensions at the center of his messaging.

Unions reciprocated Lamb's pro-labor platform by carrying out a massive get-out-the-vote effort, which resulted in several precincts that went for Trump turning Democratic.

"Side by side with us at each step of the way were the men and women in organized labor," Lamb said in his victory speech on Wednesday. "Organized labor built Western Pennsylvania...Tonight, they have reasserted their right to have a major part in our future."

Richard Trumka, president of the AFL-CIO, celebrated Lamb's campaign in a series of tweets early Wednesday, saying the Democrat "won this race because he proudly stood with unions."

.@ConorLambPA won this race because he proudly stood with unions, shared our agenda and spoke out for our members. @PaAFL_CIO used all the passion and resources to help elect him. — Richard L. Trumka (@RichardTrumka) March 14, 2018 #PA18 result is a wake-up call for every single politician. Earning the support of working people is a high bar that must be cleared with meaningful words and actions—not blind deference to party operatives or corporate interests. — Richard L. Trumka (@RichardTrumka) March 14, 2018

Analysts argued that Lamb's razor-close victory is an "ominous sign" for Trump and Republicans in states that were previously viewed as safely red.

"Any member of Congress who won by, say, 15 points or fewer in the last cycle is deeply vulnerable come November," argued The Intercept's Ryan Grim in an email late Tuesday, before the results were finalized.

Progressives were quick to argue as the election results poured in that Democrats, too, have lessons to learn from Lamb's victory.

The primary takeaway for Democrats, they argued, should be that it was Lamb's fervent support for unions and the safety net—and not his centrist positions on other issues—that ultimately put him over the top.