Days before the first Republican debate, Donald Trump has surged into the national lead in the GOP primary race, with Wisconsin Gov. Scott Walker and former Florida Gov. Jeb Bush following, a new NBC News/ Wall Street Journal poll shows.

Trump is the first choice of 19 percent of GOP primary voters, while 15 percent back Walker and 14 percent back Bush. Ten percent support retired neurosurgeon Ben Carson.

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All other Republican candidates earn single digit backing. Texas Sen. Ted Cruz is favored by nine percent of primary voters; former Arkansas Gov. Mike Huckabee and Kentucky Sen. Rand Paul are tied with six percent support; Florida Sen. Marco Rubio clocks in at five percent; and New Jersey Gov. Chris Christie, former Texas Gov. Rick Perry and Ohio Gov. John Kasich are tied with three percent apiece. Louisiana Gov. Bobby Jindal and former Pennsylvania Sen. Rick Santorum each have one percent support, and four candidates - former HP head Carly Fiorina, South Carolina Sen. Lindsey Graham, former New York Gov. George Pataki and former Virginia Gov. Jim Gilmore - register less than one percent support.

Donald Trump - 19%

Scott Walker - 15%

Jeb Bush - 14%

Ben Carson - 10%

Ted Cruz - 9%

Mike Huckabee - 6%

Rand Paul - 6%

Marco Rubio - 5%

Chris Christie - 3%

Rick Perry - 3%

John Kasich - 3%

Bobby Jindal - 1%

Rick Santorum - 1%

Carly Fiorina - *

Lindsey Graham - *

George Pataki - *

Jim Gilmore - *

Jeb Bush is the second choice of 16 percent of respondents, with Carson, Trump, and Rubio all winning the second choice spot from 11 percent of voters.

Making the debate cut

Only the top 10 candidates – calculated by an average of the last five major national polls – will be eligible to participate in Thursday’s FOX News debate in primetime, according to the network’s rules. Incorporating the new NBC/WSJ numbers, NBC estimates that the top ten candidates at this time are:

Trump - 19.8 percent

Walker - 13.2 percent

Bush - 13 percent

Paul - 6.4 percent

Carson - 6.4 percent

Rubio - 6.2 percent

Huckabee - 5.8 percent

Cruz - 5.8 percent

Christie - 3.2 percent

Kasich - 3.2 percent

Those missing the cut are:

Perry - 2.6 percent

Santorum - 1.4 percent

Jindal - 1.4 percent

Fiorina - 0.6 percent

Pataki - 0.6 percent

Graham- 0.4 percent

Gilmore - 0 percent

Trump’s rise

It has been a rapid ascent for Trump, who declared his presidential run just over six weeks ago. In early June, just one percent of GOP primary voters called Trump their first choice for the GOP nod.

His surge has come at the expense of other Republican hopefuls. Bush’s support has fallen from 22 percent last month to 14 percent now, Walker has seen a decrease of two percentage points, and Rubio’s standing has dropped from 14 percent support in June to just five percent support now.

Trump is running first with independent-leaning Republican primary voters, winning 19 percent of their support. And he captures about a quarter of GOP voters who say that they could not see themselves supporting Jeb Bush for president in 2016.

Those who say they consider themselves conservative are equally split between Trump and Walker, with about 18 percent backing each man.

And Tea Party supporters most favor Ted Cruz (22 percent), with Trump (20 percent) and Walker (20 percent) close behind.

The NBC News/ Wall Street Journal poll was conducted July 26-30, 2015. The margin of error for 252 interviews among Republican Primary Voters is ±6.17%

This story originally appeared on NBCNews.com