Donald Trump won primaries in Connecticut, Delaware, Maryland, Pennsylvania and Rhode Island on Tuesday. Barring a miracle, the reality television star will enter the Republican National Convention in July with hundreds more delegates and millions more votes than Texas Sen. Ted Cruz or Ohio Gov. John Kasich.
Cruz and Kasich are plotting to block Trump from securing the 1,237 delegates he'll need to win the nomination on the first ballot at the convention in Cleveland. Cruz hopes to then be nominated on the second ballot.
But Trump has a secret weapon: If Cruz steals the nomination, Trump could run as a write-in candidate. Trump "most likely wouldn't win as an independent candidate or a write-in candidate," says John Sides, a political science professor at George Washington University. But he could run -- or threaten to run -- as a spoiler, blocking any chance of the Republicans winning the White House in November.
The threat alone may be enough to secure Trump a spot at the top of the GOP ballot.
Some state deadlines for applying to appear on the presidential ballot as the nominee of a new party will have passed by the date of the Republican National Convention.
But the deadlines for write-in candidates are much later, so Trump could still ask his loyalists to write in his name if he's denied the nomination.
It's not that far-fetched of a prospect: Trump has near-universal name recognition. He has demonstrated a remarkable ability to attract free media attention -- around $2 billion worth, so far -- without spending much on campaign ads. He has a willingness to defy party elites, and, if he's denied the nomination, a good reason to do so. And write-in candidates don't always lose: Lisa Murkowski, who currently represents Alaska in the Senate, won her last race as a write-in, besting Republican nominee Joe Miller.
Forty-two states permit write-ins in the general election for president, according to Richard Winger, a leading expert on ballot access rules. Most of those states require that write-in candidates file some basic paperwork to have their votes counted, but the deadlines for that paperwork are later than the deadlines for appearing on the ballot as the representative of a new party.
"The earliest deadline for write-in filing is Florida, which is in July," Winger explained. Florida is an exception: Most states' deadlines for write-in candidates are later.
"Almost all the write-in filing deadlines are in October, and a few are in September," Winger said. "One is in August." These dates are all after the Republican National Convention, meaning that Trump could credibly threaten to run as a spoiler write-in candidate if he doesn't get what he wants in Cleveland.
"The question is whether Trump wants to put in the work to meet state requirements and then whether he wants to put in the work to remind voters to write in his name," Sides says. But seven states -- Iowa, Mississippi, New Hampshire, Oregon, Pennsylvania, Rhode Island and Vermont, which are collectively worth 53 electoral votes -- don't require even that basic paperwork. Trump could get write-in votes for him counted in those states in November without doing anything at all. That could mean big trouble for Cruz: Some of the most realistic paths to a Republican win in November will require him to win at least one of those states.
Voters won't even need to remember how to spell Trump's name. "For over 100 years, state courts have been ruling that the intent of the voter must be respected, so misspellings must be counted if it seems clear what the voter meant," Winger said. "This was litigated in Alaska in 2010 and Lisa Murkowski write-ins were counted even when the voter didn't spell her name right."
But whether write-in votes for Trump get counted may not ultimately matter. What matters is whether he can credibly threaten to spoil Cruz's White House chances if he's denied the nomination. The law is clear: He could get write-in votes for himself counted in seven states with no work at all, and in another 35 with just a bit of work. The threat is clear, too: A poll released Monday found that 56 percent of Trump's supporters would vote for him if he ran as an independent in the general election.
CORRECTION: This article previously stated that the deadline to appear on the presidential ballot in many states has passed. It has not, but some states' deadlines will have passed by the time the Republican Party holds its convention in July. Language has been updated accordingly.
Editor's note: Donald Trump regularly incites political violence and is a serial liar, rampant xenophobe, racist, misogynist