Donald Trump Leads Marco Rubio by 16 Points in New Florida Poll

PHOTO: Republican presidential candidates Donald Trump and Marco Rubio speak during the CNN Republican presidential debate at the Ronald Reagan Presidential Library and Museum, Sept. 16, 2015, in Simi Valley, Calif.PlayMark J. Terrill/AP Photo
WATCH Marco Rubio, Ted Cruz Question Donald Trump's Conservatism

With 19 days to go before the Florida Republican primary, GOP front-runner Donald Trump has opened up a 16-point lead over Sen. Marco Rubio.

The Quinnipiac poll result is a red flag for the Rubio campaign. The junior senator from Florida has failed to win any of the early nominating contests and faces an absolute must-win situation in Florida, where he has a home-field advantage. A Trump victory in the swing state – as well as its 99 delegates – would be a major win and potentially seal his path to the nomination.

Texas Sen. Ted Cruz earned 12 percent support in the poll, with Ohio Gov. John Kasich at 7 percent and retired neurosurgeon Ben Carson at 4 percent.

Trump leads among men, as well as voters who cited the economy, terrorism and immigration as their most important issues in the poll.

Each remaining challenger to Trump faces make-or-break contests in their home states as well. Cruz faces a pivotal match in Texas next Tuesday, and Kasich will face off in Ohio on March 15, the same day as the Florida primary.

Trump has the support of nearly every demographic group, including a 50 percentage point lead among voters who want a candidate with strong leadership.

Trump has flexed his electoral muscle during three of the early nominating contests – New Hampshire, South Carolina and Nevada. Cruz won the first-in-the-nation caucus state of Iowa nearly a month ago.

This Quinnipiac University poll was conducted from Feb. 21-24 among 705 Florida likely Republican primary voters. It has a margin of error of +/- 3.7 percentage points.

Get real-time updates as this story unfolds. To start, just "star" this story in ABC News' phone app. Download ABC News for iPhone here or ABC News for Android here.