In the presidential nominating contests of recent decades, the middle of March has told the tale.
By St. Patrick's Day, we expect to know one, if not both, of the major party nominees. Usually, the rest of the election season is just a mopping-up operation. Of course, it's been hard to find such clarity in 2016, the year that defies nearly every expectation at every turn.
Yet with the latest round of voting, we can see a trajectory and calculate a timetable for Hillary Clinton and Donald Trump to reach their goals: amassing the needed number of delegates before convention time.
On Tuesday, Trump and Clinton both won Florida, North Carolina, Illinois and apparently Missouri (though the margins there are so small that The Associated Press has not yet called the race). Clinton also added the crucial state of Ohio, making for a potential sweep of events on the primary day with the second-most delegates available all year.
It should be noted this was the first voting day that included four top-10 states by population (Missouri is 18th). Ohio had a special significance as perhaps the pivotal contest of the night and the month — and Clinton won there by nearly 14 points. (More about Ohio in a moment.)
So will Trump and Clinton ultimately be nominated? Things still may not work out that way, and powerful forces are still moving to prevent these front-runners from wrapping their respective nominations before the conventions. But stopping either of them now will require major turnarounds in momentum and math, most likely driven by some unforeseen and powerful event.
Here's why: Clinton now owns such a lead in pledged delegates (and such an exaggerated lead among the so-called superdelegates) that only a total reversal of fortune could deny her the 2,383 delegates she needs on the first ballot in Philadelphia in July.
It is still mathematically possible, and states still to vote offer a little more than half the total delegate count. But rival Bernie Sanders will need to win consistently, and win with big margins, to pull even.
"This is another Super Tuesday for our campaign!" shouted a hoarse Clinton to a cheering crowd in West Palm Beach, Fla. She congratulated her rival, Sanders, on his spirited challenge.
That challenge had taken on new force since Sanders defied the polls to win Michigan in a squeaker on March 8. His campaign had spoken of a path to winning a majority of the pledged delegates before the convention, and the next several weeks include half a dozen states where the Vermont senator is still expected to do well.
That list begins with Arizona on March 22, and Sanders addressed a wildly enthusiastic crowd in Phoenix on Tuesday night. Speaking for nearly an hour, Sanders visited his proven themes: Wall Street power, corruption in campaign finance, a "rigged economy" and income inequality. But he did not mention the results of that day's primaries.
In her speech, Clinton sounded as if Sanders were once again in her rearview mirror and her gaze was fixed forward on November and Trump.
"When we hear a candidate for president call for rounding up 12 million immigrants, banning all Muslims from entering the United States, when he embraces torture, that doesn't make him strong, it makes him wrong," she told the crowd.
Not far away, at his Mar-a-Lago Club's ornate ballroom, Trump hailed his victories as well. "We're going to win and win and win for our country," Trump said. He urged Republicans everywhere to unite behind his candidacy, adding that he'd had friendly telephone calls with House Speaker Paul Ryan and Senate Majority Leader Mitch McConnell.
"We have to bring our party together," said Trump, suddenly earnest about unity. "We have something that actually makes the Republican Party probably the biggest political story in the world."
Trump was certainly the biggest story in the Republican world again this week. Even without allocating Missouri's delegates, Trump now leads his nearest competitor by 225 delegates, with no sign of slowing down.
It is now all but impossible for anyone but Trump to reach the 1,237 delegates needed for nomination. Texas Sen. Ted Cruz has a mathematical chance, but it is remote. No other candidate has even that.
In a field of Republican candidates that initially numbered 17, Trump has now outlasted all but Cruz and Ohio Gov. John Kasich, who won his home state last night — his first first-place finish of the year.
Not so fortunate was Florida Sen. Marco Rubio, once thought the rising star of the party and the last hope of its establishment element after older and more experienced office holders fell by the wayside. Rubio had made Florida's winner-take-all primary his last stand.
On Tuesday night, having lost to Trump in most every demographic in a 19-point beatdown, Rubio tried to console his grieving supporters. He told them the Republican establishment had failed to understand the pent-up anger of conservatives.
"From a political standpoint, the easiest thing to have done in this campaign is to jump on all of those anxieties," Rubio said, adding that he had rejected that approach for a campaign of hope and aspiration.
"I ask the American people do not give in to the fear, do not give in to the frustration. The politics of resentment against other people will not just leave us a fractured party — they're going to leave us a fractured nation."
Rubio made clear he would be interested in running again. But in the near term, he will need to deal with the resentment of Cruz supporters who may blame him for dividing the anti-Trump vote in recent contests. Internet threads and social media sites were filled with arguments between backers of the two rival Cuban-American candidates, born five months apart and now both first-term senators.
No states were called for Cruz on Tuesday night, but he did finish second in three and add modestly to his stash of delegates.
"Only two campaigns have a plausible path to the nomination: ours and Donald Trump's," Cruz said. "Nobody else has any mathematical possibility whatsoever." Cruz added an appeal to those who had backed Rubio to join him.
"We welcome you with open and welcoming arms," Cruz said, inviting backers of other former candidates as well.
Neither Trump nor Cruz seemed overly concerned with the third candidate still in the Republican race, Kasich, who remains far behind with just 138 delegates to date. Clearly, the Kasich hope is to stay alive through the remaining primaries and caucuses, winning here and there and arriving in Cleveland as the hometown "favorite son" in position to be a dark-horse alternative to Trump and Cruz — both of whom are off-putting to many mainstream Republican donors and office holders.
He also has the benefit of representing a swing state, or what might be called the ultimate swing state. When you listen to people talk about American politics, you will hear someone say "it all comes down to Ohio." Because it often does.
Most recently, in 2004, flipping just over 100,000 votes in the Buckeye State would have made John Kerry president and denied George W. Bush a second term. And no Republican has ever won the White House without carrying Ohio. As he gave his rambling and emotional victory speech, Kasich stood under a sign that read: "As Ohio Goes, So Goes the Nation."
That idea could also inspire the eventual Republican nominee to choose Kasich as running mate when the ticket is finally formed. That honor might also go to Rubio, whose state is even larger and more crucial in the Electoral College. But Rubio has been far more outspoken in his verbal spats with both Trump and Cruz, and might need the convention to be quite disrupted indeed before it turns to him.