The Senate Leadership Fund spent $37 million over the last two weeks of the election and around $165 million total. The group rescued the National Republican Senatorial Committee, which had essentially run out of money by October after pounding Democrats in Pennsylvania, Ohio and New Hampshire. GOP donors rushed to the fund as they panicked over Donald Trump’s presidential prospects, with Sheldon Adelson and his wife contributing $20 million.

“That’s the only reason, in my view, that we’re competitive,” Holmes said in an interview.

For most of the 2016 election cycle, Republicans believed that keeping the Senate was a lost cause. Their map was bad: -- defending two-dozen seats to defend vs. just 10 for Democrats -- and their nominee, the thinking went, made it that much worse.

Yet rather than get swamped by an anti-Trump wave, Republican Senate candidates across the country were lifted to victory by their erratic standard bearer. As Democrats squabbled internally over how their incoming leader Chuck Schumer and the Democratic Senatorial Campaign Committee were doling out money to different states, it turned out no amount of money or tactical shift would be enough.

Until the end, Democrats remained confident they had put enough states on the board to pick up the minimum five seats they would need. Instead they got clobbered nationwide.

And when the Senate Leadership dumped their last $12 million into Senate races, it included more than $2 million for Wisconsin -- a state that Democrats long believed was in the bag and Republicans had written off for most of the campaign.

The comeback

Indeed, even as late polls showed Republican Sen. Ron Johnson closing the margin with Democratic Sen. Russ Feingold, GOP strategists in Washington thought Johnson had a hard ceiling in the state.

More than any other vulnerable GOP Senate candidate, Johnson went all-in for Trump.

“Our nominee is a change agent,” Johnson declared in one debate with Feingold. “I’m a change agent.”

In the closing days of the campaign, Johnson joined Trump on the trail for the first time. (He and North Carolina’s Richard Burr were the only at-risk incumbents to do so.) And Johnson’s chances were boosted when Trump’s campaign aired $6.2 million in ads down the stretch in Wisconsin, while Clinton spent just $646,000 in the state.

Feingold, meanwhile, went about three weeks without directly attacking Johnson on air, sticking mostly to positive ads. Senate Democrats’ campaign arm spent almost nothing in the state, figuring other candidates needed more help than Feingold.

At the same time, a newly-hired admaker, Scottie Howell, began airing ads touting “the Ron Johnson you don’t know.” It showed the senator volunteering in impoverished communities and reuniting parents with adopted children.

“[Howell] actually made Ron Johnson likeable. It was unbelievable,” one Republican official said of the famously blunt Wisconsinite.

Johnson defeated Feingold by more than 3 points in the biggest Senate upset Tuesday night.

Upending the Senate map

Other, earlier strategic decisions paid off for Republicans in spades.

After Sen. Marco Rubio’s (R-Fla.) vowed during his presidential campaign not to run for reelection to the Senate if he lost, Republicans were left with an assortment of second-tier candidates. Instead of picking one, party officials rushed back to Rubio.

Ward Baker, the NRSC’s executive director, began quietly talking with Rubio, who swore Baker to secrecy. McConnell summoned Rubio to his office in April after chatting policy on the Senate floor and didn’t mince words: We need you to run.

And when McConnell pressed Senate Republicans in late May to encourage Rubio to run again, Sen. Bob Corker (R-Tenn.) buttonholed him on the Senate floor.

“You can see when somebody has a spring in their step, and you can see when they don’t, you know?” Corker said of Rubio after the two talked. “It was just very noticeable to me.”

Rubio’s June 22 announcement that he would break his pledge and run for reelection was a huge relief for Republicans who were struggling all over the map to keep seats in play. But their fortunes seemed to turn weeks later when Democrats scored a last-minute star recruit of their own: Evan Bayh, a former governor and senator who came with $10 million in his campaign account to boot. Immediately, polls showed him with a big double-digit lead.

GOP Rep. Todd Young’s campaign, advised closely by former McConnell aides Holmes and John Ashbrook, felt they wouldn’t win if they tried to shred the record of a former popular governor. Instead, Republicans had to persuade enough Indiana voters that Bayh changed after leaving the Senate.

Young’s campaign knew their messaging was working when the results of their “verbatims” – when pollsters ask voters open-ended questions, and those answers are recorded – returned. The campaign made word clouds of the answers, and when voters were asked what they didn’t like about Bayh, two phrases stuck out: “lobbyist” and “not from Indiana.”

Not long after, Bayh’s lengthy personal Senate schedules that detailed meetings with banking lobbyists, health care executives and future employers began to leak. Bayh’s unfavorability rating skyrocketed. The DSCC and Senate Majority PAC, once so confident Bayh could win on his own, were forced to divert resources to the state.

“No one thought his schedules were going to leak,” one Democratic official said. “It’s unprecedented.”

Bayh lost badly on Tuesday night.

A different kind of Trump wall

As Florida faded, Democrats scrambled for a path back to the majority. In a conference call with Sen. Roy Blunt’s (R-Mo.) campaign staffers on Aug. 27, the NRSC’s Baker was asked about the status of Blunt’s race.

“We’re going to lose,” Baker responded. The NRSC executive director was firm, even though public polls still had Blunt ahead of Democratic Secretary of State Jason Kander.

The Missouri senator’s campaign didn’t take that news well. And two days later Democrats’ attacks on Blunt as a D.C. insider came into focus when Blunt was spotted at a farmer’s market in D.C.’s swanky Palisades neighborhood, instead of barnstorming Missouri.

Yet Trump ran so strongly in the conservative state that he pulled Blunt across the finish line, despite bipartisan praise for Kander as the best Senate candidate of the election cycle.

It was a similar story in North Carolina, where Sen. Richard Burr (R-N.C.) was frustrating Republicans with his laid-back style.

Burr wouldn’t hire campaign staff and had no campaign manager. In the spring, his campaign hired a Republican analytics firm to head up an aggressive data effort. But a few days in, the firm was told the GOP senator vetoed the expenditure because he didn’t want to spend the money.

The two-term senator held back on attacking unknown opponent Deborah Ross, who was somehow out-raising him. Then Burr said he wouldn’t start campaigning until October. By the time November came around, the NRSC had committed nearly $10 million to North Carolina.

The rescue mission paid off, as Burr rode Trump’s coattails in another state expected would be theirs. Democrats’ road through conservative states ended abruptly.

Portman puts it away

In May, when Senate Democrats and Majority PAC laid down their ad reservations, Ohio looked to be Ground Zero in the race for the Senate. Sen. Rob Portman (R-Ohio) was viewed as vulnerable, and a slew of polls showed former Democratic Gov. Ted Strickland as a slight favorite.

But last summer, Portman campaign manager Corry Bliss spotted an interesting e-mail from Strickland’s personal assistant Chris Cupples gleaned from a Freedom of Information Act request in the first batch of research he ordered up on Strickland.

“Ted is taking a nap now,” Cupples wrote to deputy chief of staff Janetta King in 2007 after King emailed regarding a media inquiry about strip club regulations. The e-mail was sent at 12:10 p.m. on Tuesday. From that moment on, Bliss decided to mock Strickland as tired and washed-up.

“We started putting the words ‘low-energy’ in our releases,” he said, adopting Trump’s famous put-down of Jeb Bush. A staffer dressed up in a tire dubbed “Retread Ted,” stalked Strickland around the state; the same staffer set up a recliner outside one of Strickland’s campaign offices to take a “nap.”

But Strickland had bigger problems than a mascot. He was a lackluster fundraiser who was prone to gaffes, and was never able to find his footing. As Portman absorbed millions in attacks ads, he only gained in the polls – and Democrats decided to pull the plug.

“I joked with my colleagues when I would go back during the last year or so that I was absorbing a lot of the heat,” Portman said. “Schumer and Harry Reid were not shy about trying to knock me out.”

Handling Trump

Baker was convinced as far back as August 2015 that Trump would be the Republican nominee. But when the NRSC chief told a group of Senate chiefs of staff that month there was an “88 percent chance” it would be Trump, they laughed him out of the room.

He was unbowed. A month later he prepared a lengthy white paper on how to run alongside Trump and began coaching candidates individually. His main advice: run hyper-local “sheriff’s race” campaigns. And don’t count on riding the traditional coattails of the Republican presidential nominee.

But Democrats had determined that Republicans wouldn’t be rewarded if they equivocated on Trump in a staid focus group in Pittsburgh in August of this year. Voters heard statements from Sen. Pat Toomey (R-Pa.) waffling on his party’s nominee and concluded he was just trying to save his own hide.

“They do not give him the benefit of the doubt,” said a Democratic official who observed the focus group.

Yet Toomey, who waited until Tuesday night to disclose that he voted for Trump, didn’t seem to suffer. He pulled out a narrow win against Democrat Katie McGinty.

How to position themselves vis-a-vis Trump vexed vulnerable Republicans all year. But, a month before the election, it became a code-red emergency when decade-old video Trump boasting about forcing himself on women using language even Howard Stern wouldn’t condone.

New Hampshire GOP Sen. Kelly Ayotte woke up the next morning and made up her mind: She had reached her breaking point. Against the advice of some of her political advisers, she announced she’d rather lose the election than keep standing by Trump.

On Wednesday morning, her opponent, Democratic Gov. Maggie Hassan, declared victory, even though the Associated Press has yet to call the race and Ayotte isn’t ready to concede. While Hassan has a small lead among counted ballots, it was narrow enough for the incumbent to demand a recount.

Rep. Joe Heck also quickly disavowed Trump. But unlike Ayotte, Heck made his announcement on camera, and in a state where he couldn’t afford to lose many Trump backers and still prevail.

The once-promising GOP recruit for Reid’s seat was on the ropes. And Democrats finished him off in the final weeks with an overwhelming show of force by Reid’s political machine and capped by a blistering appearance by President Barack Obama. The president wondered aloud “what the heck” Heck was thinking still backing Trump.

“They just took what he said and they’re running an ad for Catherine,” said Reid, who personally called Obama and asked him to make the trip.

But instead of buffeting their majority, it was the only bright spot for Senate Democrats the entire night.

Elena Schneider contributed to this report.