The writer was U.S. ambassador to Belgium from 2009 to 2013 and is managing director of the Gutman Group, an international consulting and investment group.

The United States may soon have its first female president. And it may not be Hillary Clinton.

Over the past few weeks, the best answer to the question of who will emerge as the Republican presidential nominee — businessman Donald Trump, Sen. Ted Cruz (Tex.), Ohio Gov. John Kasich, some other failed 2016 contender or even House Speaker Paul D. Ryan (Wis.) — has become “none of the above.” In each instance, the case for why any one of these candidates probably won’t be picked has gotten much stronger than the one for why each of the individual candidates would.

Despite Trump’s big victories this week, he’s not the “presumptive nominee” he claims to be. He faces much tougher challenges in Indiana and California, where poor showings would likely leave him short of the 1,237 delegates needed to end the upcoming Republican convention chaos with a victory in the first round of voting. Despised and feared by the Republican establishment, Trump almost certainly will do worse with each passing round. A stone’s throw is probably as close as he’ll ever get to the nomination.

Cruz is on track to succeed as the spoiler of the Trump campaign. But with Trump romping on the East Coast, Cruz will likely finish hundreds of delegates and millions of votes behind. That’s too far back. The possibility of allowing a big loser to leapfrog over a clear front-runner has not polled well among the party rank and file. It’s a good bet it will flop at the convention, too.

If it could, the Republican establishment would settle for finding its way to Kasich, Sen. Marco Rubio (Fla.), new Cruz running mate Carly Fiorina or another one of the 2016 also-rans. But if the leap over Trump is too great for Cruz, the chasm will be prohibitive for a bigger loser.

For these reasons, much of the inside money recently shifted to Ryan. The scenario is powerful and straightforward: You have a deadlocked convention; choosing one of the three finalists is sure to fracture the party; the last nominee, Mitt Romney, is more bad dream than fond memory; and there sits Ryan, offering appeal to a broad spectrum of Republicans.

But even as this answer began to look better in recent weeks, the spotlight it turned on Ryan quickly became something of a glare. Whether or not it was of his own doing, Ryan began to look as though he was undermining the democratic process by angling for the job. Threatened with a damaging loss of credibility and harboring no great desire to be a sacrificial lamb in a losing year, Ryan shifted his denials from coy to resolute. Now, even if his heart still yearns for 1600 Pennsylvania Ave., he may have slammed the door too forcefully to reopen it.

Still, someone has to do the job. Someone with more to gain than lose. Someone whose star is still rising. And someone who’s in the fortunate position of being able to avoid Ryan’s fate of looking as though she’s trying to disrupt democracy by stealing the nomination from the voters.

Enter Nikki Haley. Generally beloved by the establishment and the insurgent outsiders in the Republican Party, the South Carolina governor is among the few who seek out the cameras without looking like a 2016 subversive. She has license to engage with the media all the way to Cleveland. And since any eventual nominee is certain to see in her a strong asset on the campaign trail, a Cabinet official or even a potential running mate, her reputation will stay unsullied as the daggers continue to fly. She can in all good faith even continue to believe — or at least act as though she believes — that all she is doing is helping put the best face on her party in a moment of need. Ignorance can be such profitable bliss.

But the understudy often fills in when the lead goes down. With “none of the above” becoming ever more obvious as Cleveland gets closer, Haley’s convention speaking slot may need to be moved to Thursday night.