The narrowing of a vast field of Republican US presidential hopefuls begins in earnest with the first television debate of the 2016 campaign.
At stake for Republicans is not only picking the candidate to represent them in the election, but also selecting the direction the party will take as it seeks to regain the White House.
As in the 2012 Republican primaries, the party faces a tug of war between those eager for a candidate with broad election appeal and those who think the key to winning is nominating a fiery conservative.
"You're starting off with a lot of candidates who have an initial group of support that reflect a particular element of the party, but nobody is close at this point to putting together a majority coalition," said David Winston, a Republican pollster.
But this time, the field of 17 candidates is both larger and more seasoned, making the choice Republicans will ultimately make less certain or inevitable than in past elections.
While Republicans say they relish their options, its doubtful many expected the summer surge of businessman and reality television star Donald Trump.
Although still a long-shot candidate, the real-estate mogul will stand at centre stage during today's prime-time debate in Cleveland, thanks to his status as the top performer in several recent national polls following a string of outlandish statements.
Only 10 candidates were invited by debate host Fox News to participate in the main event, with the remaining seven relegated to a pre-debate forum.
With his unpredictable style and unformed policy positions, Mr Trump does not fit neatly into any one segment of the Republican Party, which appears to be a draw for a section of the party's base frustrated with Washington and career politicians.
But some Republicans fear his comments - whether about Mexican immigrants or the war record of Senator John McCain - will taint the public's view of the party as a whole.
"A problem-solver that isn't a career politician is something that's appealing to many people," said Michigan governor Rick Snyder, a Republican. "But I would hope it could be done in the context of not being offensive to people."
Standing to Mr Trump's left on the debate stage will be former Florida governor Jeb Bush, a favourite of the wealthy donors and business leaders that populate the establishment wing of the Republican Party.
But like Mitt Romney, who filled that role in 2012 before ultimately claiming the nomination, Mr Bush has struggled to break away from the rest of the field.
The son and brother of former presidents, he also faces questions about whether his nomination would mark a return to the past.
To Trump's right on the stage will be Wisconsin governor Scott Walker, whose victories over unions in his home state created his national profile.
Florida senator Marco Rubio, the youngest candidate in the field at the age of 44, is trying to carve out a niche as a foreign policy expert, but has struggled to break through this summer - particularly since Mr Trump's surge.
A host of candidates with sharply conservative records and attention-grabbing personalities will seek to pull the party far to the right.
They include Texas senator Ted Cruz, surgeon and anti-tax tea party favourite Ben Carson, and former Arkansas governor Mike Huckabee, a popular choice among evangelicals and social conservatives. Kentucky senator Rand Paul adds a libertarian twist to the field.
Rounding out the top 10 are a two governors. New Jersey's Chris Christie is a past favourite, while Ohio's John Kasich is a latecomer to the race whose first campaign for president 16 years ago never took off.
The debate is the first of six scheduled before primary voting begins in February.
Fox News used five national polls to decide which 10 candidates would be on the stage, and among those bumped to the earlier forum are former Texas governor Rick Perry and businesswoman Carly Fiorina, the only woman in the field.