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

Republican candidate Donald TrumpDonald John TrumpOn North Korea, give Trump some credit Exclusive: Bannon says Rosenstein could be fired 'very shortly' GOP dissidents on cusp of forcing immigration votes 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 CruzPoll: Cruz leads O'Rourke by 7 points Freedom Caucus bruised but unbowed in GOP primary fights Five races to watch in the Texas runoffs 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 CarsonDems expand 2018 message to ‘draining the swamp’ This is how Republicans should shape message to win elections Dems to target GOP corruption in midterms: report MORE and Sen. Marco RubioMarco Antonio RubioRepublicans think Trump is losing trade war The Hill's 12:30 Report — Sponsored by Delta Air Lines — Trump meets South Korean leader as questions linger about summit with North Senators demand answers on Trump’s ZTE deal 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.