To the degree Americans think of Libya, most support the United States’ limited involvement in its civil war. But Republicans and Democrats in Congress are still right to ask questions about the endeavor, whether they back entry into this Muslim arena or oppose it.

That said, President Barack Obama on Monday offered a strong, clear view on why we’re involved, even as our troops seek to extract themselves from Iraq, get a handle on fighting in Afghanistan and assist our fallen ally Japan. Considering his passivity of late, he struck us as forceful, even presidential, in his speech to the National Defense University.

Certainly he answered key questions, including the strategic rationale for our role in NATO bombing raids targeting Col. Moammar Gadhafi, including the fact Libya is a powder keg between Tunisia and Egypt — two nations extremely vulnerable as their people strive to put together new, hopefully democratic governments after forcing out long-entrenched regimes.

He also offered a convincing argument for not leaping straight into the fray. He stressed the need to forge international partnerships rather than going it alone. He noted how our military response in Bosnia in the 1990s, when people were being slaughtered, took more than a year to assemble. By contrast, the United States took only 31 days with Libya.

All well and good. Yet the president’s explanation for intervening to stop the slaughter of Libyans by their government begs questions when so many nations expect us to be the world’s policeman. Are we willing, for instance, to spend another billion dollars or so to halt harsh crackdowns by the Syrian government on its people? How do we explain this to taxpayers watching their services cut or threatened in America? If the Arab League, which sought our involvement in Libya, wants us there, why don’t they at least foot the bill?

The president did offer some criteria for when the United States might consider military involvement in such humanitarian undertakings in the Middle East: an international mandate for action, the support of Arab countries and a broad coalition prepared to join us in the mission.

We continue to have deep reservations about our involvement in this faraway civil war. We also have great anxiety about those whose side we’ve taken. We believe, as U.S. Sen. Kay Bailey Hutchison noted Monday, that it does not diminish our standing in the world to allow one of our allies to assume the lead in Libya. Even so, we acknowledge that the president’s speech offers starting points to discuss when deciding whether to employ our military in places where we seem to have no vital interests — let alone any business.