The battle for the Senate won’t be decided until the January run-offs in Georgia, and yet the inevitability of a razor-thin majority means that the stock of the moderate Manchins and Murkowskis is already going through the roof.
A clutch of Republican moderates — Alaska’s Lisa Murkowski, Maine’s Susan M. Collins and Utah’s Mitt Romney — appear poised to wield outsized power if the Alaska seat goes as expected to Republican Sen. Dan Sullivan, and just one of the two Georgia seats stays red.
“If I were investing in senators, I would invest in Susan Collins, Lisa Murkowski and Mitt Romney,” said Ross Baker, political science professor at Rutgers University. “They really will, I think, assume an enormously influential position in the 117th Congress.”
The path to a Senate majority is more difficult for Democrats, but if they prevail, look for Sen. Joe Manchin III of West Virginia, the chamber’s most conservative Democrat, to become the party’s critical swing vote.
A Jan. 5 run-off victory by either Georgia incumbent, Sens. David Perdue and Kelly Loeffler, would give Republicans 51 seats, putting the formidable political skills of Senate Majority Leader Mitch McConnell to the test in keeping the caucus united.
“The challenge for Sen. McConnell is to hold those three in on close votes,” Mr. Baker said. “The challenge for [Senate Minority Leader] Chuck Schumer is to try to lure them across the line on close votes.”
On the other hand, if Democrats run the table in Georgia, they would move from 48 to 50 senators, with the tie being broken by the vice president — which, unless the Trump campaign upends the vote count in key states, would be Democrat Kamala D. Harris.
Under that scenario, all eyes would be on Mr. Manchin, particularly on energy and climate change issues, which would have major repercussions for coal country.
He could have some company in the blue dog caucus with Sen. Bob Casey of Pennsylvania and Democratic newcomers John Hickenlooper of Colorado and Mark Kelly of Arizona, who are expected to trend to the center on some issues.
As the two-term governor, Mr. Hickenlooper, a geologist by training, was a champion of Colorado’s oil-and-gas industry over the objections of the state’s powerful environmental movement, at one point drinking fracking fluid to prove its safety.
Mr. Kelly, the former astronaut, may be best known for his gun-control advocacy, but he also represents voters who backed former Vice President Joseph R. Biden while reelecting Republicans to majorities in both houses of the state legislature, defying predictions of a blue wave.
Republican strategist Michael McKenna challenged the rising-moderates speculation, saying that “we get this sort of conversation in the wake of every election.”
“I’m sure that some point a group of moderates will coalesce and exert their influence,” said Mr. McKenna, whose column appears in The Washington Times. “I’m equally certain that this Congress will not be that time.”
He said it’s more likely that moderate Democrats will split with their party on crucial votes than the other way around, given Mr. Biden’s aggressive agenda on issues such as taxes and energy.
Any push by Mr. Biden to follow through on raising taxes and clamping down on the oil-and-gas industry “will tend to lead senators into their respective corners,” Mr. McKenna said in an email.
“It’s a challenge to compromise with someone who wants you to take your money and your job,” he said. “It is more likely that moderate (and energy state) Democrats — Manchin, Casey, Hickenlooper — will wind up voting with Republicans more often than they would have if Mr. Trump had remained president.”
Tight Senate majorities have been the rule rather than the exception since 2009, when Democrats enjoyed a 60-seat lead and leveraged it to pass the Affordable Care Act, signed by President Obama.
The senator to watch most closely in the 117th Congress may be Ms. Murkowski, who faces reelection in November 2022. Ms. Collins was reelected last week and Mr. Romney doesn’t go before the voters until 2024.
“What McConnell cares about is being majority leader and not minority leader,” Mr. Baker said. “If Lisa Murkowski needs to do something that is going to cause her to vote with the Democrats, he’ll give her the OK. He’ll greenlight it for her if it’s important to Alaska.”
Republicans to date have lost net one Senate seat with losses by Sens. Cory Gardner of Colorado and Martha McSally of Arizona, and the defeat of Sen. Doug Jones, Alabama Democrat, to Republican Tommy Tuberville, the former Auburn football coach.
In Georgia last week, Mr. Perdue fell just short of hitting the 50% threshold needed to win the seat outright. Instead, he and Democrat Jon Ossoff, who won 47.9% of the vote to Mr. Perdue’s 49.7%, will meet again in a runoff.
Ms. Loeffler, who was appointed to fill the Senate vacancy in 2019, will square off against Democrat Raphael Warnock after no candidate reached 50% in the crowded Nov. 3 jungle primary.
If Republicans take both Georgia Senate seats, the party would hold a 52-vote majority — just one seat shy of their current 53 seats.
That isn’t much of a surplus, even with Vice President Mike Pence as the deciding vote, and yet Mr. McConnell typically gets his way when the chips are down, moderates or no moderates.
“Assuming Republicans win in Georgia, it will be Sen. McConnell’s world,” Mr. McKenna said. “We will just live in it.”