The New York Times reports: President Obama said Tuesday that the United States would formally recognize a coalition of Syrian opposition groups as that country’s legitimate representative, intensifying the pressure on President Bashar al-Assad to give up his bloody struggle to stay in power.

Mr. Obama’s announcement, in an interview with Barbara Walters of ABC News on the eve of a meeting in Morocco of the Syrian opposition leaders and their supporters, was widely expected. But it marks a new phase of American engagement in a bitter, nearly two-year-long conflict that has claimed at least 40,000 lives, threatened to destabilize the region, and defied all outside attempts to end it.

The announcement puts Washington’s political imprimatur on a once-disparate band of opposition groups, which have coalesced, under pressure from the United States and its allies, to develop what American officials say is a credible transitional plan to govern Syria if Mr. Assad is forced out.

Moreover, it draws an even sharper line between those elements of the opposition that the United States champions and those it rejects. The Obama administration coupled its recognition with the designation hours earlier of a militant Syrian rebel group, Al Nusra Front, as a foreign terrorist organization, affiliated with Al Qaeda.