Why Donald Trump Isn't Winning Over Late-Deciding Voters

— -- There's no doubt Republican presidential candidate Donald Trump has shown dominance in early states so far -- especially in Nevada, where he won almost every demographic group according to entrance polls.

But there is one potential Trump weak spot that has emerged from entrance and exit polling data: his struggle to win late-deciding voters.

A whopping five in six Trump supporters in Nevada said they made up their minds more than a week before voting started. Only 17 percent of his backers made up their minds in the final week – compared to a third of Ted Cruz’s supporters and half of Marco Rubio’s supporters who decided in that time frame.

Voters on the fence have not been supporting Trump. Among the three in 10 Nevada GOP voters who made up their minds in the final week, Rubio won four in 10 of them, compared to about a quarter for Trump and Cruz each. Cruz has also seen more success than Trump with late-deciders, though slightly less than Rubio.

Similar patterns appear in other early voting states, with Trump winning just 14 percent of late-deciders in Iowa and 17 percent of late-deciders in South Carolina – both behind Rubio and Cruz in states where almost half of voters made final decisions in that time period.

In New Hampshire, Trump won over the most late-deciders, largely because of the splintered field of viable candidates.

The low support from late-deciders isn't likely to hurt Trump much. But if the voters who are reluctant to settle on a candidate choose Trump's competition in the eleventh hour of a head-to-head matchup, chalking up crucial wins for the businessman-turned-presidential candidate could prove difficult.

This comes as new sense of urgency is driving the GOP establishment to consolidate around one candidate to face Trump. But with friendly contests in their home states less than three weeks away, Rubio, Cruz and John Kasich insisted they were staying in the race for the long haul.

Still, roughly three in four Trump supporters who have voted so far committed to Trump at least a full week before they voted for him, a sign of dogged commitment to Trump from his followers, but also a sign of reluctance from indecisive voters on Trump.

On the other hand, more than half of Rubio’s total supporters in early states have made up their minds in the week before the election – a higher proportion than Trump’s in every state so far.