March 1 was Super Tuesday in the campaign for the U.S. presidency, but March 15 is shaping up to be a key date in determining the nature of the Republican race.
Businessman Donald Trump, leading in national polls for months, has used that support to win the most state primaries and caucuses so far. But while the once-massive Republican field has dwindled to five candidates, there have been calls for Republicans to unite behind a single opponent who can earn enough delegates to prevent a Trump nomination.
As of March 15, candidates can start earning all of a state's delegates with a win rather than just a portion based on their percentage of the vote. It's also when two key states – Florida and Ohio – have winner-take-all primaries.
Republican strategist Ford O'Connell said it would take two more weeks for the decisions on who stays in the race and for how long.
"I think that determination will be made on the 15th whether they're going to have a two-man race or pack it all in for a stretch run to the convention," O’Connell said.