Latest Fox poll before debate: Trump leads, Bush second

Trump leads with 26 percent of the vote, followed by Bush at 15 percent, Scott Walker at 9 percent and Ben Carson at 7 percent. Ted Cruz and Mike Huckabee poll at 6 percent apiece, Rand Paul and Marco Rubio are each tied at 5 percent.

If the Fox poll is indicative of who will qualify for the main Thursday debate the network is holding, Chris Christie and John Kasich would round out the participants at 3 percent each. Rick Perry, Bobby Jindal, Rick Santorum and Carly Fiorina are among the high-profile candidates who would fail to make the cut.

Trump has gained support since the last Fox News poll in mid-July, when he took 18 percent of the vote, and in June, when he was polling 11 percent. Bush is up 1 point from July, when he was getting 14 percent. Walker has fallen from 15 percent in the previous Fox poll.

The percentage of Republicans who said they would “never” vote for Trump dropped 26 points from 59 percent in June to 33 percent in the current poll. The share of Republicans who say they will “definitely” vote for him has more than quadrupled from 8 percent to 34 percent over the same time period.

Trump leads among Tea Party supporters with 33 percent and evangelical Christians with 22 percent, two important subgroups of conservative GOP voters.

Among the Democrats, Hillary Clinton leads with 51 percent of the vote. That’s down 10 points from June, but she’s still beating her nearest rival by 29 points. Bernie Sanders is running a distant second at 22 percent and Joe Biden is in third with 13 percent. Martin O’Malley, Jim Webb and Lincoln Chafee received 1 percent apiece.

The poll of Republican voters has a margin of error of plus or minus 6 points, the Democratic poll plus or minus 4 percentage points. The first Republican presidential debate will take place on Thursday in Cleveland, Ohio. Only the top ten candidates based on national polling will be included.