By Kyle Trygstad and Alexis Levinson, CQ Roll Call (MCT)

WASHINGTON — The 2014 battle for the Senate has featured a few candidate bumbles and some colorful characters.

So far, it’s lacked any cycle-defining gaffes — “Todd Akin moments” — but there are still a few days to go until Election Day and potentially two runoffs extending things into early next year.

Every election cycle provides noteworthy events or moments in time that, in hindsight, proved to be pivot points in the outcome. Roll Call has identified ten such instances that helped define this cycle’s Senate landscape.

In 2012, Sen. Olympia J. Snowe’s (R-ME) last-minute retirement began to alter the conventional wisdom that Republicans were likely headed for the majority. Months later, comments about rape by Todd Akin and Richard Mourdock sealed the deal for Democrats.

Now, once again, the majority is up for grabs: Republicans have pushed the fight into purple states, while Democrats are holding out hope the party can hang on.

Here are ten moments that helped get us here, in chronological order:

Hollywood star declines McConnell challenge (March 27, 2013)

There is little doubt an Ashley Judd-Mitch McConnell race would have garnered plenty of attention, but it’s unlikely the actress could have put up as strong a fight against the Senate minority leader as has Democrat Alison Lundergan Grimes.

Although McConnell remains favored in the Kentucky race, Grimes has pushed the Republican in one of the most expensive races of the cycle. Two weeks after Judd announced in a series of tweets that she wouldn’t run, a bizarre story unfolded from a Mother Jones report on a secret recording of a McConnell campaign meeting where opposition research on Judd had been discussed. Lundergan Grimes jumped in the race three months later.

Herseth Sandlin decides not to run (May 13, 2013)

Former Rep. Stephanie Herseth Sandlin’s decision not to run for Senate in South Dakota all but ended any hopes Democrats had of holding the seat. The Republican-leaning state would have been a tough race for Democrats in the best-case scenario, but with Sen. Tim Johnson (D-SD) retiring, there was little shot without a top recruit, such as Herseth Sandlin.

Her decision to pass, which came shortly after the senator’s son made clear he would not pursue the seat, left Democrats without a strong candidate to contest the seat.

There was a brief ray of light for Democrats in early October, when poll numbers showed Democratic nominee Rick Weiland and independent Larry Pressler closing on Republican nominee Mike Rounds. Democrats dropped $1 million into the race to capitalize on that, but Republicans matched them, and this race has slid back into the Republican column.

Schweitzer shocks Democrats (July 13, 2013)

Heading into the state Democratic Party convention, former Montana Gov. Brian Schweitzer was widely expected to announce he would seek the seat of retiring Sen. Max Baucus. But on a Saturday morning in the middle of the confab, Schweitzer declared he would not run, leaving Democrats in a lurch and giving Republicans the upper hand.

Had he run, most or all of the events that followed would never have happened: Democratic Lt. Gov. John Walsh entered the race, GOP Rep. Steve Daines entered the race, Baucus resigned, the governor appointed Walsh to the seat, The New York Times uncovered extensive plagiarism by Walsh in a graduate school paper, Walsh dropped out of the race.

Gardner in, Buck out (Feb. 26, 2014)

When we look back on the 2014 midterms, there may be no more pivotal moment than the day in late February when Republicans pulled off a smooth candidate swap in Colorado between the 4th District and Senate races. National Republicans worked for months to recruit Rep. Cory Gardner, who represented a safe seat, to take on Democratic Sen. Mark Udall, who was headed for a likely victory over Republican Ken Buck. But Buck, back after losing a winnable race against Sen. Michael Bennet in 2010, agreed to run for Gardner’s seat, clearing a path for Gardner and putting Colorado in jeopardy for Democrats.

Brown announces preparations for New Hampshire Senate bid (March 14, 2014)

The 2014 Senate map always looked good for Republicans. Between the Democratic retirements and the Democrats facing re-election — most of them in Republican-leaning states — the GOP had the potential to pick up at least a handful of seats. But former Sen. Scott P. Brown’s decision to challenge Sen. Jeanne Shaheen (D-NH) put the Granite State on the map for Republicans and fueled the narrative of just how good a year this could be for the party. And though Shaheen still has the edge, New Hampshire could be the bellwether for a Republican wave: If Brown wins, it’s going to be a good night for the GOP.

Hog castration and farmers hit the air waves (March 25, 2014)

This fateful day set the course for the rest of the Iowa Senate race, helping move what had been a lower-tier race directly onto the competitive playing field.

Joni Ernst, then one of five Republicans vying for the nomination, released an ad about her experience castrating hogs. (Technically, the ad was released on March 24, but most publications wrote about it the next morning.) The ad went viral, catapulted Ernst to national recognition and helped her win the nomination by an overwhelming margin. She avoided the convention Democrats had hoped for and received a significant boost in fundraising.

On the same day, America Rising released video of Democratic Rep. Bruce Braley denigrating Sen. Charles E. Grassley (R-IA) as “a farmer from Iowa who never went to law school.” Republicans seized on the comment, which Braley quickly apologized for, to define the congressman as elitist and out of touch — a theme that has carried through the entire race.

Tillis shows up to the State House to preside as speaker (May 14, 2014)

Republicans are scrambling to push Thom Tillis over the edge in the race to unseat Sen. Kay Hagan (D-NC). Many Republicans privately attribute that state of affairs to Tillis’ decision not to step down as speaker of the state House when he won the nomination. One week after the primary, Tillis reported to Raleigh to preside over the “short session” of the general assembly. When he emerged three months later, after the contentious session finally came to a close, a poor second-quarter fundraising haul and a barrage of Democratic ads had him back on his heels.

Cochran wins the Republican runoff (June 24, 2014)

His challenger was still contesting the result until last week, but Sen. Thad Cochran pulled off a miracle by defeating Tea Party-backed Chris McDaniel in a runoff after finishing behind him in the primary.

Cochran’s supporters weren’t as engaged, but his campaign and key allies were able to expand the electorate — which could include anyone who didn’t vote in the Democratic primary — and increase the number of anti-McDaniel voters.

Cochran’s victory wiped the state off the map for national Democrats, who, with former Rep. Travis Childers as their nominee, would have added it to the party’s nearly barren plank of offensive opportunities had McDaniel prevailed.

Democratic nominee drops out of the Kansas Senate race (Sept. 3, 2014)

Sen. Pat Roberts did not have as easy a path to re-election as he had anticipated. But in a state as Republican-leaning as Kansas, all of that was supposed to be over after the primary.

Then Chad Taylor, the Democratic nominee for Senate, dropped out, leaving Roberts in a one-on-one race with independent businessman Greg Orman. Unlike Taylor, Orman had done well fundraising, was airing television ads, and polled ahead of Roberts in a head-to-head match up. Suddenly, Republicans had to scramble to save the unprepared incumbent — and their shot at gaining the six seats they need for a Senate majority.

Perdue is proud of outsourcing record (Oct. 6, 2014)

As a first-time candidate, former corporate CEO David Perdue took an on-the-job lesson in political crisis communications one month before the general election. At a campaign stop in early October, the Republican, who faces Democrat Michelle Nunn in the Georgia Senate race, was asked about a recent report that he’d professed to outsourcing jobs most of his career. “Defend it? I’m proud of it,” Perdue said.

The Nunn campaign would go on to cut three TV ads on the issue within a week, Nunn took small leads in two public polls, and outside money began flowing in from both parties, as the race — which could go to a Jan. 6 runoff — emerged as a potential majority decider.