It’s a long shot, but it could work — provided the party is willing to accept the substantial short- and long-term risks.

But to get there, they need to keep Trump from amassing an outright majority of delegates. Only then will they be able to pick a new nominee.

With Donald Trump continuing to outpace all rivals at the primary polls, some Republican leaders are considering a desperate, rear-guard effort to keep the polarizing candidate from winning the party’s nomination: a brokered convention.

For instance, if Trump feels spurned by the party, he could mount a scorched-earth third-party write-in campaign to sap support from the ersatz nominee. Meanwhile his supporters, having had their millions of votes effectively nullified by a few thousand insiders, could be lost to the Republicans for years to come.


Can the party really defy the will of the voters?

Most years, this problem simply doesn’t come up. During the months-long primary process, Democratic and Republican voters generally settle on a candidate who’s perfectly acceptable to party leaders. And that candidate consistently gets an outright majority of delegates, which secures the nomination.

This year is something different. Republican voters are flocking to a candidate who is anathema to many party insiders. More to the point, it looks like Trump may struggle to get an outright majority of delegates, which is what makes a brokered convention possible.

The math is far from certain, but if Ted Cruz can capitalize on Marco Rubio’s departure from the race, gaining new voters and new opportunities to defeat Trump in upcoming primaries, then Trump might come up short of delegates, depite being well ahead of all his rivals.

And when no candidate can claim a majority, convention delegates get a lot more latitude to follow their own personal preferences rather than the voters’ choice. This is what a brokered convention is all about.


How does a brokered convention actually work?

Keep your eyes on the delegates; that’s the secret to understanding a brokered convention.

Each primary or caucus ends by divvying up delegates. In some winner-take-all states, the candidate with the most votes gets every delegate. Other times, they’re distributed proportionally, with the leader getting the most delegates and lower finishers fewer.

It’s vital to remember, though, that these delegates are real people with real ties to the Republican party machinery. When you hear that Trump won 50 delegates in South Carolina, that doesn’t mean he gets to pick a bunch of people who will go to the convention and represent him. To the contrary, members of the South Carolina Republican party will separately choose their own 50 people and send them off with orders to vote for Trump at the start of the Convention — but only at the start.

Most state delegates have this same responsibility. They are told how to vote on the first ballot, and are left free after that.

So if there’s no winner on the first ballot — no candidate with a majority of the votes — predictability quickly evaporates. Suddenly, many delegates are free to vote for whomever they like, including people like Mitt Romney or Paul Ryan who aren’t even running.

After that, the dealing begins. It may take some time but after a failed first ballot the delegates have no choice but to talk and vote and negotiate until some person captures a decisive, majority share.


Assuming Trump fails to win a majority on the first ballot, his fate will lie in the hands of these unbound delegates, who aren’t necessarily his biggest fans.

Who set up this process?

The Republican Party controls the rules, and they still have time to change those rules.

One issue getting attention is Rule 40, which says that a candidate has to win a majority of the delegates in at least eight states in order to be considered for the nomination. It’s a high bar, and depending on how things unfold, Trump may be the only one to clear it — which would effectively make him the nominee.

Odds are that Rule 40 will be amended before the convention begins. And there could be other Trump-unfriendly rule changes along with it.

New rules require the support of convention delegates, but here again is where the party-friendly status of these delegates matters. Many of them may be obligated to vote for Trump, but that won’t necessarily stop them from supporting anti-Trump rules.

Could the party survive a brokered convention?

This is the big question. If Trump amasses the largest share of votes and the party still finds a way to deny him the nomination, the backlash could be historic.

True, Trump has repeatedly pledged to support the ultimate Republican nominee, but it’s not clear that extends to cases where he’s ousted in a convention coup. And while it might be too late for him to register as a third-party candidate, he could still vacuum away votes by urging supporters to write in his name or stay home.


Perhaps more worrying for the long-term viability of the Grand Old Party, a spurned Trump could conceivably set up a competing right-populist party, potentially splitting the right for years to come.

Even if we set these risks aside, though, and assume Trump graciously accepts his loss, a brokered convention could still bring a once-in-a-generation reckoning with voters newly aware of the impotence of their input.

In the early 20th century, and again in the 1960s and 70s, voters fought for greater involvement in the candidate selection process. And the resulting system has mostly worked, reducing the prominence of backroom deal-making and moving the nomination fight into the voting booth.

A brokered convention in 2016 might tear away the veneer of democratic legitimacy propping up the current system and force a new fight between people and parties over who controls the presidential primaries.

More from Evan Horowitz:

Evan Horowitz digs through data to find information that illuminates the policy issues facing Massachusetts and the U.S. He can be reached at evan.horowitz@globe.com. Follow him on Twitter @GlobeHorowitz