It's a long time until the Iowa caucuses, but Thursday night's Fox News debates among the 17 Republican presidential candidates gave a good indication of which candidates to watch in the months ahead. The experience of the 2012 primaries, when a different Republican held the lead in the polls seemingly every week, demonstrates the folly of trying to predict the outcome much in advance, particularly given the divisions within the GOP. Nonetheless, it was possible to see how the candidates are positioning themselves and who has the potential to break out in the months ahead.

Who the other Republicans should fear


Before the candidates worry about who can beat the Democrat — and here, they're pretty much all assuming that will be Hillary Clinton — they need to win over Republican primary voters and caucus goers, and many of the candidates Thursday night were clearly trying to ignite the passions of the party's base. Unfortunately, with so many making the same pitch, it's going to be hard to accomplish that. Many analysts' pick Wisconsin Gov. Scott Walker as someone who could rise from the pack, stuck to his absolutist bona fides on abortion, but he's got loads of competition for the social conservative vote, particularly from former Arkansas Gov. Mike Huckabee, Dr. Ben Carson and, from farther back in the pack, former Sen. Rick Santorum. Mr. Walker can also point to his public employee union-busting successes in Wisconsin, but the ranks of current and former governors in this race who can boast conservative management is a long one. He emerged unscathed from the debate, but he didn't catch fire, either.

Two who did show potential for stirring the passions of the base were former Hewlett-Packard CEO Carly Fiorina and Sen. Ted Cruz of Texas. Ms. Fiorina lags in the polls and was relegated to the 5 p.m. undercard debate with seven other second-tier candidates. But she made the most of her time with sharp, focused, forceful answers. More importantly, she emerged as a Fox News darling. During the main event, the moderators played two clips from the earlier debate: one of Ms. Fiorina, and another of former Texas Gov. Rick Perry praising Ms. Fiorina.

Meanwhile, if Republican primary voters are looking for who would be the purest conservative — and many are — Mr. Cruz emerged as the obvious choice. His willingness to go after establishment figures in his own party for failing to live up to their conservative promises speaks straight to the tea party movement.

Who the Democrats should fear

If it's a long time until the primaries, it's even longer until the general election. Still, three candidates showed clearly how they could position themselves to speak to the broader electorate. Florida Sen. Marco Rubio showed a genially combative nature combined with a forward looking message. He was convincing when talking about the economic struggles he and his family have experienced and in positioning himself as the "nominee of the future." Former Florida Gov. Jeb Bush has figured out how to answer the question about whether he, like his brother, would have invaded Iraq, and his embrace of education reform gives him a unique agenda that can resonate across political lines.

But the big winner in this category was clearly Ohio Gov. John Kasich. He can match the other governors in the economic and fiscal turnaround category. He deftly capitalized on his experience in Washington as a congressman in the 1990s, and most of all, he was able to express his conservatism in a compassionate way. His answer to a question about gay marriage was a bravura performance — he stuck to his opposition without sounding bigoted. It's not the right side of history, or even the right side of current public opinion, but it's the needle a successful Republican candidate is going to have to thread in 2016.

Who everybody should fear

Sen. Rand Paul and New Jersey Gov. Chris Christie clearly both wanted to be the candidate who appeals to those disaffected by politics and politicians. Mr. Christie has the blunt, tough talk, and Mr. Paul has the cut-against-the-grain views. But both were trumped, if you'll pardon the pun, by businessman/entertainer/self-promoter Donald Trump. Anyone who was hoping he would wither in the glare surely came away disappointed on Thursday. His ugly, misogynistic treatment of Fox host Megyn Kelly during the debate and particularly afterward will hurt him among people who were never going to vote for him anyway. His supporters come from an angry segment of the electorate, and the one thing he could do to turn them off at this point would be to apologize.

Plenty of people see America's political and economic system as rigged. Mr. Trump is saying it is, that he knows exactly how it's rigged and that he's exploited it himself. That's a tough message for his opponents, who mainly are a product of the political system he sneers at, to combat. We cannot imagine that Mr. Trump could win the Republican nomination, much less the presidency, but so long as he's in the race, either as a Republican or an independent, he will be the center of attention.