Space got a few moments in the limelight in January as the fight for the Republican U.S. presidential nomination heated up in Florida, but the public exchanges among the leading candidates yielded little from which an observer might discern a realistic and achievable direction for NASA’s rudderless human spaceflight program.

Not surprisingly, former House Speaker Newt Gingrich stirred the pot by declaring that the United States would begin colonizing the Moon by the end of his second term if he were elected president come November. This would be accomplished, he said, by turning over more of NASA’s functions to the private sector and devoting 10 percent of the space agency’s $17 billion-plus annual budget to cash prizes rewarding innovations or milestones achieved in support of the goal.

Mitt Romney, the former Massachusetts governor and now undisputed front-runner for the Republican nomination, ridiculed the idea of a lunar colony, saying it would cost hundreds of billions if not trillions of dollars. During debates in Florida Jan. 23 and 26, Mr. Romney waxed on the importance of space exploration and NASA, and said his administration would chart a path for space following a dialogue involving the academic and scientific communities, the military and the private sector, which would be asked to share the financial burden.

Mr. Gingrich’s idea is essentially U.S. President Barack Obama’s space exploration policy on steroids: visionary, to be sure, but hardly realistic. If U.S. industry saw a potential pot of gold on the Moon, it would be investing its own money to get hold of it. As it is, President Obama’s far less ambitious bid to commercialize crew transportation to and from the international space station is heavily dependent on government funding and encountering as many hiccups as one might expect from a traditional NASA development effort.

To his credit, Mr. Romney resisted the temptation to court voters on Florida’s shuttle-deprived Space Coast with an emotionally appealing but unrealistic exploration vision of his own. But he shed little light on the direction NASA’s highest-profile program would take in a Romney administration.

With Florida’s primary now in the rearview mirror, space policy is likely to resume its usual place in presidential campaign politics: in the background. But the general election is just around the corner, and with Florida likely to be a hotly contested battleground, space could once again emerge as an area where Mr. Romney can distinguish himself.

President Obama’s plan for NASA is well established and leaves much to be desired. Even if his commercialization strategy succeeds in restoring independent U.S. crew access to the international space station — something a more traditional, straightforward government procurement approach might have accomplished sooner — the president has failed to articulate a realistic vision for what comes next and why. He did offer a notional goal of visiting an asteroid by 2025, but has since done little if anything to demonstrate his seriousness about this objective.

Mr. Romney was savvy enough to see a vulnerability there, which he demonstrated in taking shots at President Obama’s space policy during the Florida debates. But saying the president has no vision for space exploration is one thing; coming up with a realistic and compelling alternative is an entirely different matter.

The GOP front-runner has won the endorsement of several prominent figures in the space exploration community, including former NASA Administrator Mike Griffin; Bob Crippen, who piloted the first space shuttle mission; and Gene Cernan, the last man to walk on the Moon. But so far, all the general public truly knows about Mr. Romney when it comes to human spaceflight policy is that he is neither President Obama nor candidate Gingrich. That proved not to be much of a liability during the Florida Republican primary, as Mr. Romney’s runaway victory attests. But voting dynamics in a general election are different, and just a few hundred votes could make the difference in the all-important swing state of Florida. If Mr. Romney, who has pledged to reduce government spending as president, has something more to offer — in other words, a realistic and compelling space exploration plan — he would impress some voters, particularly in Florida, by giving them a glimpse in the months ahead.