THE SENATE has approved trade-promotion authority for President Obama that, if the House follows suit, will enable the administration ultimately to bring a completed free-trade deal, the Trans-Pacific Partnership (TPP), to both houses for an up-or-down vote. This action is a great victory for the president, who aggressively lobbied wavering members of his party, and for Senate Majority Leader Mitch McConnell (R-Ky.), who piloted the measure past every last-minute obstacle its opponents threw up.

This bipartisan vote was also, we’re obliged to say, a victory for truth. We understand the concerns of the bill’s opponents, because, well, they’re understandable. Trade-promotion authority represents a substantial transfer of power by the legislative branch to the executive; such trust is never to be extended lightly, least of all in a matter that affects not only the terms on which the United States will trade with a vast portion of the world but also its geopolitical position in the strategic Pacific Rim. Yet in their zeal to prevent a feared sellout of U.S. workers, opponents of both the trade-promotion bill and the TPP have resorted to distortion and hyperbole that’s excessive even by Washington standards.

The Senate did many things by approving trade-promotion authority; first and foremost, it returned U.S. negotiators to the bargaining table fully empowered to cut their best deal on behalf of the American people. What the upper house decidedly did not do, however, was bless some nefarious, corporate-controlled secret process that’s bound to result in job destruction for the United States — much demonizing rhetoric of the bill’s opponents to the contrary notwithstanding. As the administration has repeatedly, and correctly, pointed out, members of Congress have and will continue to have ample opportunity to inform themselves about the content of the TPP long before they have to vote on it. The vast bulk of the trade affected by the deal would be with high-wage, high-labor-standard countries such as Japan, Australia and Canada. If approved, the TPP would fortify a U.S.-Japan strategic relationship that is vital to checking undue Chinese influence in Asia.

Our list of heroes in the Senate should include the 13 Democrats — including Virginia Sens. Mark R. Warner and Timothy M. Kaine — who voted to end debate and let the bill proceed to a vote, despite tremendous pressure from powerful interest groups in their party. As we said, however, the hard-fought Senate triumph is only the prelude to a potentially even more difficult showdown in the Republican-majority House, where the anti-free-trade leanings of the Democratic caucus could merge with far-right Republican hostility toward Mr. Obama to produce a defeat. Much will depend on how many Democrats in that body follow the example set by their pro-engagement colleagues in the Senate. It’s heartening that two local representatives, Gerald E. Connolly (D-Va.) and John Delaney (D-Md.), are supporting the president. If the bill is to be assured of passage, though, more House Democrats, from this area and elsewhere, will have to do so as well.