Trump now up 21 points over closest competitor, Cruz
© Greg Nash

Republican candidate Donald TrumpDonald John TrumpIvanka Trump pens op-ed on kindergartners learning tech Bharara, Yates tamp down expectations Mueller will bring criminal charges Overnight Cybersecurity: Equifax security employee left after breach | Lawmakers float bill to reform warrantless surveillance | Intel leaders keeping collusion probe open MORE added 3 points in a new CNN/ORC International poll released early Wednesday to expand his commanding lead over the GOP presidential field.

Trump now has the support of 39 percent of Republicans independents who lean Republicans.

Sen. Ted CruzRafael (Ted) Edward CruzWhatever you think the Alabama special election means, you’re probably wrong This week: Congress gets ball rolling on tax reform Week ahead: Senators work toward deal to fix ObamaCare markets MORE (R-Texas) strengthened his second-place standing, adding 2 points since a similar poll in early December. He currently has 18 percent support.

Ben CarsonBenjamin (Ben) Solomon CarsonPrice resignation sets off frenzy of speculation over replacement We are all to blame for the Las Vegas shooting India's IBM conquest is an ominous sign for American industry MORE and Sen. Marco RubioMarco Antonio RubioOvernight Defense: Tillerson, Trump deny report of rift | Tillerson says he never considered resigning | Trump expresses 'total confidence' in secretary | Rubio asks Army to kick out West Point grad Rubio asks Army to kick out West Point grad with pro-communist posts GOP establishment doubts Bannon’s primary powers MORE (R-Fla.), who both saw their support fall in the new national poll, are tied for third, with 10 percent apiece.

No other GOP contender had more than 5 percent support.

Trump is widely seen as the candidate most capable of handling the major issues facing the nation today.

A strong majority, 57 percent, said the billionaire businessman would be the best Republican primary contender to deal with the economy. His closest competitors are Cruz at 8 percent and Rubio at 7 percent.

Fifty-five percent also said they trust Trump most on illegal immigration, followed by Cruz at 15 percent and Rubio at 10 percent.

And despite never holding elected office, 47 percent said Trump would be preferred as commander in chief in the ongoing fight against the Islamic State in Iraq and Syria (ISIS).

The poll also found that Trump's support is largely comprised of non-college-educated voters. Among those without a degree, 46 percent back Trump, while only 27 percent of graduates said they support his candidacy.

The poll of 1,018 adults was conducted Dec. 17 to Dec. 21, following the last GOP debate on Dec. 15 in Las Vegas. It has a margin of error of 3 percentage points.

--Bradford Richardson contributed to this report, which was updated at 7:48 a.m.