Allies of former Vice President Joe Biden Joe BidenFormer Pence aide: White House staffers discussed Trump refusing to leave office Progressive group buys domain name of Trump's No. 1 Supreme Court pick Bloomberg rolls out M ad buy to boost Biden in Florida MORE argue that state-level election results on Tuesday make a powerful case for his White House candidacy.

From deep-red Kentucky to rust-belt Pennsylvania and battleground Virginia, Democrats performed especially strongly in the suburbs, where moderate voters proliferate.

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Democratic margins among those voters were central to the party taking full control of the government in Virginia, making gains in Pennsylvania and — apparently — enabling Democratic challenger Andy Beshear to oust incumbent Gov. Matt Bevin (R) in Kentucky.

Bevin has requested a recanvass in the Bluegrass State, where Beshear’s lead is about 5,000 votes, or less than half a percentage point.

Overall, Biden allies assert that the results offer a template. They argue he is better placed than left-wing rivals such as Sen. Bernie Sanders Bernie SandersSirota reacts to report of harassment, doxing by Harris supporters Republicans not immune to the malady that hobbled Democrats The Hill's Morning Report - Sponsored by Facebook - Republicans lawmakers rebuke Trump on election MORE (I-Vt.) or Sen. Elizabeth Warren Elizabeth WarrenOvernight Defense: Appeals court revives House lawsuit against military funding for border wall | Dems push for limits on transferring military gear to police | Lawmakers ask for IG probe into Pentagon's use of COVID-19 funds On The Money: Half of states deplete funds for Trump's 0 unemployment expansion | EU appealing ruling in Apple tax case | House Democrats include more aid for airlines in coronavirus package Warren, Khanna request IG investigation into Pentagon's use of coronavirus funds MORE (D-Mass.) to replicate Tuesday’s triumphs on a national scale.

One Biden ally said Tuesday’s results prove that the country is in the center.

“No one is running on ‘Medicare for All’ and winning,” the Biden ally said. “Voters clearly want a moderate, not someone who appeals to just the fringes of one party.”

This has been the core of Biden’s appeal since he entered the presidential race in April.

The animating principle of his campaign is that he is the best person to beat President Trump Donald John TrumpFederal prosecutor speaks out, says Barr 'has brought shame' on Justice Dept. Former Pence aide: White House staffers discussed Trump refusing to leave office Progressive group buys domain name of Trump's No. 1 Supreme Court pick MORE because he can appeal to moderates, is culturally simpatico with voters in the crucial Rust Belt and Midwest in particular, and can be less easily tagged as an extremist than Sanders or Warren.

His left-wing rivals vigorously contest that analysis.

Supporters of progressive candidates argue that the country is hungry for fundamental change, and that Biden will ultimately fall flat because he is offering the electorate something less compelling.

When it comes to Tuesday’s results in particular, some strategists are skeptical that serious lessons for the presidential race can be extrapolated at all — at least as far as the battle between progressives and centrists is concerned.

Democratic strategist Zac Petkanas said that Trump himself was the big issue on Tuesday and will likely remain so a year from now.

"What the election results prove is that Donald Trump is deeply unpopular and that the election will be a referendum on his presidency,” Petkanas said. “In Kentucky, the Republicans ran ad after ad trying to paint Beshear as a left-wing radical and that clearly didn't do a lick of damage and the person Republicans can thank is Donald Trump … This should buoy the hopes of every candidate running for president.”

Although some see Beshear’s win in Kentucky as a textbook example of how a moderate Democrat can attract center-ground support — Beshear is considered a classic centrist and did not emphasize impeachment during his campaign — Petkanas demurred.

"The idea that [Beshear] won because he is a moderate Dem is just ridiculous. Republicans didn't paint him as a moderate. They painted him as a left-wing wackadoodle,” he said.

Overall, he added, “Whether you are Warren, [South Bend, Ind., Mayor Pete] Buttigieg [or] Biden you should feel good for what this means for 2020. The idea that this only helps moderates is pure spin.”

The centrist versus progressive battle is central to the Democratic presidential primary nonetheless. And the available evidence provides enough ammunition for both sides.

A new series of battleground state polls from The New York Times and Siena College, published Monday, suggested Biden runs more strongly against Trump than do either Sanders or Warren. But the margins were hardly definitive.

The polls tested the three leading Democratic candidates in hypothetical match-ups against Trump in the six states that went to the president by the narrowest margins in 2016: Arizona, Florida, Michigan, North Carolina, Pennsylvania and Wisconsin.

Biden was beating Trump in five of those states, compared to Sanders in one and Warren in none.

However, the differences were often within the polling margin of error.

For example, the poll showed Biden winning Pennsylvania by a single point, Sanders losing by the same margin and Warren losing by 2 points.

Not many Democrats would want to put much money on those outcomes holding a year from now — even though the general contours of the polling help Biden’s case.

The picture is also increasingly complicated because Buttigieg is picking up momentum in the centrist lane that has so far been dominated by Biden.

In Iowa, in particular, Buttigieg is performing strongly. The 37-year-old mayor has bested Biden in the last three major polls to emerge from the Hawkeye State.

Still, there is a case to be made that the results on Tuesday bolster Biden’s appeal.

“Suburban voters that were key to Democratic victories last night in Virginia, Kentucky and Pennsylvania races that received less attention are critical to Biden's electability argument, giving his campaign and narrative a bit of a boost," said Democratic strategist Basil Smikle.

Andrew Bates, a spokesman for the Biden campaign, said on Wednesday that the former vice president was "thrilled with last night's results which reflect an energizing message that brought Americans together around strengthening the [Affordable Care Act] and enacting common sense gun reforms. Donald Trump is scared of nothing more than having to face this kind of approach next year."

Another Democratic strategist, who is unaffiliated with any campaign, said the results "should be a wake-up call for all Democrats.”

"You can't just come up with pie in the sky proposals and expect to win," the strategist said.