GOP front-runner Donald Trump widens his lead in the nomination race, while Marco Rubio and Ted Cruz threaten to overtake Ben Carson for the number two spot.

Those four once again constitute the top tier in the latest Fox News national poll on the 2016 election.

In addition, Rubio joins Carson as the only candidates at least half of voters say are honest and trustworthy -- though Carson’s honesty rating has taken a hit. More on that later.

First, here’s how the GOP race stands: Trump remains in the top spot with a record 28 percent support from Republican primary voters. He was at 26 percent in the last Fox poll, which was completed before the last debate and the Paris attacks (November 1-3, 2015).

Carson drops from 23 percent to 18 percent in the new poll. Cruz and Rubio are both up three points and garner 14 percent each.

All others are in the low single digits: Jeb Bush gets 5 percent, while Chris Christie, Carly Fiorina, and Mike Huckabee each get 3 percent. John Kasich and Rand Paul receive 2 percent a piece.

CLICK HERE TO READ THE POLL RESULTS

Three key GOP constituencies put the four favorites in the upper-tier: the Tea Party, white evangelical Christians, and talk radio listeners.

Among GOP primary voters who are part of the Tea Party movement, Trump is the first choice (38 percent), followed by Cruz (30 percent). Carson (14 percent) comes in third -- receiving less than half of Trump’s support. Rubio rounds out the quartet with 9 percent.

About a quarter of white evangelical Christians back Trump (25 percent) and Carson (24 percent), while Cruz gets 18 percent and Rubio receives 11 percent.

Cruz (31 percent) is the preferred pick among those who listen to conservative talk radio daily. Trump (24 percent), Rubio (16 percent) and Carson (11 percent) also get double-digit backing.

Honest and Trustworthy Revisited

Earlier this month, Carson was the only 2016 candidate deemed honest and trustworthy by a majority of voters: 60 percent said he was (November 1-3, 2015). Since then, some reporters -- and Trump -- have questioned whether everything in Carson’s new book is true.

The attacks seem to have pushed Carson’s honesty ratings down: today 53 percent of all voters say he is honest, while 34 percent say he isn’t. Still, that’s a net positive of 19 points, which gives him the second highest honesty score (the total percentage points of those saying you’re honest minus those saying you’re not) of the candidates included in the poll.

Rubio does a touch better on that measure. By a 51-31 percent margin, voters say he is honest and trustworthy (+20 points), up from 41-36 percent earlier this month.

Cruz (+11 points), Fiorina (+5 points) and Bush (+4 points) also get positive honesty scores.

Trump gets a negative 14 honesty score (41 percent honest vs. 55 percent not). That still puts him ahead of Hillary Clinton. She receives a net negative 20 score (38 percent honest vs. 58 percent not). Clinton’s ratings hit a record low in early November when just 35 percent of voters said she was honest.

Among self-identified Republicans, all of the GOP candidates tested have a positive net honest and trustworthy score: Carson (+56 points), Cruz (+51 points), Rubio (+46 points), Fiorina (+35 points), Bush (+32 points) and Trump (+24 points).

Seventy-three percent of Republicans say Carson is honest, down from 82 percent in early November.

The Fox News poll is based on landline and cellphone interviews with 1,016 randomly chosen registered voters nationwide and was conducted under the joint direction of Anderson Robbins Research (D) and Shaw & Company Research (R) from November 16-19, 2015. The poll has a margin of sampling error of plus or minus three percentage points for all registered voters, and 5 points for Democratic primary voters and 4.5 points for Republican primary voters.