Opinion writer

Washington periodically defers, as do Rome and Qom, to the judgments of the impressively robed — the ex cathedra portion of the political season. The constitutional implications of the Supreme Court’s health-care ruling will be debated until Election Day and dissected beyond it. But it is the court’s immigration decision — and Mitt Romney’s positioning on the issue — that throws the brightest light on the presidential race. And the glare is not kind to the challenger.

Some have faulted Romney for a muddled response to the ruling — a tactical criticism that is largely unfair. It is difficult to be clear about an ambiguous decision. (The constitutionality of Arizona’s “papers, please” law seems to depend on the politeness with which police deliver the “please” part.) Romney aides also note that their candidate is uncomfortable with the whole enterprise of a president, or prospective president, cheering or jeering the actions of the Supreme Court in the manner of a pennant race. An admirable reticence.

Romney’s whole post-primary approach to immigration — recently summarized in his speech to the National Association of Latino Elected and Appointed Officials — has been careful and reasonable. He faults President Obama for election-year urgency on immigration policy after 31 / 2 years of passivity. He highlights the scandal of double-digit Hispanic unemployment. He calls for easier family unification for permanent residents, green cards for those earning advanced degrees, and a path to legal status in exchange for military service.

Considered individually, these messages and policies make sense. Taken together, they are a strategic failure. Romney is being careful and reasonable on immigration in the midst of a five-alarm political fire. Latino support for Republicans has been dropping since conservatives blocked President George W. Bush’s attempt at comprehensive immigration reform. Romney accelerated the descent by pledging to veto the Dream Act as president. His polling among Hispanics now bumps along at about 25 percent — a level that seems inconsistent with winning Colorado, Nevada or perhaps even Florida. It is an uphill political task merely to match John McCain’s level of Latino enthusiasm. Attaining even this modest goal will require an outreach strategy bolder than “Keep Calm and Carry On.”

On immigration, President Obama’s boldness of late has been Napoleonic. The French emperor is hardly a model for a democratic statesman, given the coup of 18 Brumaire and all that. But he knew how to throw his strength at an opponent’s weak point at a decisive moment — which Obama did with his mini-Dream Act. It was a questionable use of executive power. But after weeks of political stumbles, Obama proved capable of an audacious stroke. And it is not likely to be his last. A campaign proud of its micro-targeting has plenty of demographic groups left to motivate.

The contrast is instructive. The Obama campaign is often tactically weak — an exercise in endless speeches, overmatched spokesmen, blame-shifting and expectations-lowering. But the president is capable of ambitious repositioning.

The Romney campaign, in contrast, is focused and tactically competent. Romney is a strikingly better general-election candidate than he was in the primaries. He was always implausible claiming to be the most conservative person in a room filled with tea party activists. He is comfortable pressing the argument against Obama’s failed economic stewardship — admittedly an easier case to make.

But it should concern Republicans that the Romney campaign has shown little appetite for strategic boldness — the ability to shift an argument, exploit a weakness or appeal to an unexpected audience. Immigration is the most urgent example, but there are others. What innovative policy has Romney announced to reassure suburban women? Or to drive home his appeal to Catholic voters, whom Obama seems intent on alienating? Or to persuade working-class voters that he is committed not just to economic freedom but also to upward mobility?

This absence of strategic ambition may reflect a strategy — that the election should be only a referendum on the Obama economy. If so, it is a serious mistake. Very few coast to the presidency based on the failures of others. A challenger who does not shape his own image will have it shaped for him. A candidate who does not compete on his opponent’s home turf will often be struggling on his own.

In a stalled economy, in a period of public discontent, in a dead heat less than five months out, Romney is primed for a victory in November. But it won’t come by default.