The latest NBC News/SurveyMonkey online poll has Donald Trump back in the lead with 28% support among Republican and independent voters who lean Republican. Meanwhile, Ben Carson seems to be fading. He has lost eight points and is tied with the surging Ted Cruz for second place with 18%.

The only other candidate with double-digit support is Marco Rubio. The Florida senator is supported by 11% of Republican (leaning) voters. Rubio is followed by Jeb Bush with 4%, and by Chris Christie and Carly Fiorina with 3% each.

Carson’s campaign is in trouble because he has lost support among white evangelicals (down from 33% to 25%) and among voters who describe themselves as “very conservative” (from 30% to 15%).

Nearly all of those voters have gone to Cruz:

This NBC News/SurveyMonkey poll confirms the findings of yesterday’s PPP poll: Trump stabilizing, Carson fading, Cruz surging.

Carson has come under increased scrutiny and has made some serious gaffes, especially on foreign policy issues. That’s always a problem, but especially now. Just a week ago, terrorists struck at the heart of Paris, thereby reminding conservatives that the war on radical Islam is far from over. Apparently, they’ve concluded that the country can’t afford to nominate someone who has to learn foreign policy “on the job.”

If Carson wants to get the momentum back, he has to change the subject. Every day the media and his rivals are talking about immigration and radical Islam is a bad day for him, and a very good day for both Cruz and Trump.