The headline from a new Des Moines Register-NBC News poll of Iowa is that former President Donald Trump still has a big lead in the Republican race. Among those likely to take part in the Iowa caucuses, Trump is at 43%, with Ron DeSantis and Nikki Haley tied for second place, at 16%. So, Trump has a 27-point lead, which is actually bigger than his lead in the last Des Moines Register poll in August.

A lot of news reports are emphasizing Haley’s rise in the poll. Back in August, her support was at 6%, and DeSantis’ was at 19%. Now, she has shot up 10 points to 16%, while DeSantis has slipped 3 points to 16. So while they are in the same spot at the moment, it appears she is on the way up and he is on the way down.

But there’s bigger news than any of that in the poll. It concerns the depth of Trump’s strength.

You’ve often heard Trump opponents say they want to see the GOP field narrowed down as quickly as possible. That way, the thinking goes, the support from all the Trump opponents could come together behind one candidate to challenge Trump one-on-one. Look at Trump now, they say, with 43% support, versus everybody else with a combined 57%. Just get the rest of the field together behind one candidate, and Trump can be defeated.

The new poll shows it’s not going to be that easy. The Des Moines Register not only asked voters which candidate they supported but also which candidate would be their second choice if their first choice were no longer in the race. So they asked people who now support DeSantis: Who’s your second choice? And they found out that 41% of current DeSantis supporters, if DeSantis were to leave the race, would switch to Trump. Just 27% of them say they would switch to Haley.

So, if DeSantis were to drop out today, it appears the largest part of his support would go to Trump, and not to the mythical unity anti-Trump candidate.

For Haley, the numbers are different. Just 12% of those who support her today say they would go to Trump if she were to leave the race. But the bottom line is, there’s a flaw with the let’s-all-unite-behind-one-anti-Trump-candidate strategy. In real life, some of each candidate’s supporters would go to Trump if their favored candidate were to leave — and that makes Trump harder, not easier, to beat.

Haley appears to be attracting voters who really don’t like Trump. “To my mind, she’s done the best job of differentiating that she is the non-Trump candidate,” Des Moines Register pollster Ann Selzer said. For example, about 1 in 5 respondents in the Iowa poll call themselves independents. Back in August, Haley won the support of just 10% of them. Now, her support among independents is 22%. That’s a big move, although Trump’s support among independents is still significantly higher, at 33%.

What’s more, Haley’s voters aren’t really locked in for her. Forty-seven percent of Trump supporters say they are “extremely enthusiastic” about voting for the former president. For DeSantis, the number is 25%. For Haley, it’s 19%. “That may be a sign that although Haley is the only candidate seeing substantial upward momentum in this poll, Selzer said, the ground underneath her could be ‘a little shaky,’” the Des Moines Register reported.

Haley’s progress has been substantial. There will undoubtedly be more voices calling for the other candidates to drop out and allow Haley to challenge Trump one-on-one. But the new poll shows that is a risky proposition.

This content originally appeared on the Washington Examiner at washingtonexaminer.com/opinion/new-poll-exposes-flaw-in-trump-opponents-plan.