DES MOINES, Iowa—Around 9 p.m. on Monday night, a video from the Iowa caucus made the rounds. At one unnamed precinct, there was a tie: Both Sen. Bernie Sanders and Hillary Clinton had an equal number of supporters. But someone must win the precinct for officials to allocate delegates, and so they chose a classic solution to the problem of a tie: They flipped a coin. Clinton won the toss, and the precinct.

As analysts and observers, we will have to play this game for the Iowa Democratic caucus writ large. As of Monday night, with 95 percent of precincts reporting, there isn’t a winner. Clinton has 49.8 percent of the vote, but Sanders has 49.6 percent of the vote. As for Martin O’Malley? He withdrew from the race after receiving less than 1 percent. (Although, that small showing might make the difference in the final count between Clinton and Sanders.)

Clinton and Sanders are tied, and in their election-night speeches, neither candidate tried to pretend otherwise. Speaking to supporters in a packed gathering at Drake University in Des Moines, Clinton said she was “breathing a sigh of relief.”

“It is rare that we have the opportunity we have now to have a real contest of ideas, to really think hard about what the Democratic Party stands for,” she said. “I am excited about really getting into the debate with Sen. Sanders about the best way forward to fight for us and America.”

Not far from Clinton’s gathering, Sanders stood with his wife, Jane, to speak to a huge crowd of jubilant supporters. “Given the enormous crises facing our country, it is just too late for establishment politics and establishment economics,” he said, with shouts of “feel the Bern!” in the background.

Given the bitterness in this campaign—when Clinton declared she was a “progressive” during her speech on Monday, viewers at the Sanders event chanted that she was a “liar”—it’s hard to believe that this is just the beginning. But it is. With an almost even number of votes and delegates out of Iowa, the contest turns to New Hampshire, where Sanders holds a decisive advantage. The next fight is in Nevada—where there’s not enough polling to say anything about the race—and from there we go to South Carolina, where Clinton dominates. By the end of February, the Democratic primary will likely be where it was at the beginning of the month: divided.

As for the final outcome of the Democratic presidential primary? It’s still too early to say. But, the tie in Iowa means the basic shape of the race hasn’t changed. To win, Sanders needs to dominate in friendly states and survive in hostile strongholds. Iowa, with its young people and liberal voters, was a test of the former, and he couldn’t deliver. Put differently, as the consensus candidate of much of the Democratic Party—with strong support among people of color, Democratic moderates, and a large minority of Democratic liberals—Clinton is still favored to win the nomination. For Sanders to advance—and capture the prize from Clinton’s hands—he needs to excel, or she needs to stumble, badly. The former is a challenge, and while the latter is possible, after the 2008 primary and the surprise of Barack Obama, I wouldn’t count on it.

For anyone who followed the 2008 campaign, all of this sounds wearying. But if you are a Democrat who wants to win the White House for a third term—or a progressive who just wants to minimize the damage to your priorities—you should relish the upcoming combat. Why? Because a competitive primary will energize the Democratic Party and prime it for a tough and grueling general election.

In Iowa, for example, returns suggest turnout that either meets or exceeds the record from 2008. Across the state, caucus rooms were teeming with people eager to vote for either Clinton or Sanders. People who had never participated in their lives—from college students to retirees—were canvassing, volunteering, and otherwise giving their energy to the candidates. And we should expect something similar in New Hampshire, where both campaigns are fighting to to find and activate supporters.

Not everyone who participates in the primary will give their time, their labor, or their votes in November. But many will, and in doing so, they will strengthen the Democratic Party at a time when strength is critical, and every effort matters. If Democrats pull the unlikely feat of holding the Oval Office for a third consecutive term, they may look back at this fierce, acrimonious primary as the critical variable. Together, Sanders and Clinton have begun to make millions of moderate, left-leaning, and liberal Americans care about the outcome of November. No, as Mitt Romney’s 2012 campaign can tell you, enthusiasm doesn’t win elections. But it doesn’t hurt either. And right now, Democrats are on the path to an enthusiastic electorate.

Read more Slate coverage of the Democratic primary.