Top Republicans are looking beyond Tuesday's make-or-break primaries and preparing for a nasty nomination fight that could push all the way to this summer's GOP convention in Cleveland.

The planning, detailed in conversations with nearly a dozen party officials and strategists, is stretching from Ted Cruz campaign headquarters in Houston to the Republican National Committee's offices on Capitol Hill. And this week, following Tuesday's primaries, wealthy GOP donors — many of whom have directed millions of dollars toward defeating Donald Trump — will gather in Florida to discuss what the party's path forward looks like.

Of course, depending on Tuesday's outcome, the planning of a contested convention may be moot. Most Republican strategists contend that if Trump wins Florida and Ohio, a result well within his reach, the New York City billionaire will have virtually sewn up the nomination.

But with much of the Republican Party aligned against the GOP front-runner — and with questions persisting about whether he'll be able to assemble the 1,237 delegate-majority needed to secure the nod — some are getting ready for a prolonged, grind-it-out fight that could go on for weeks or even months.