The outcome of the presidential campaign is still in doubt, though one result - a debasement of political discourse, possibly permanent - is already evident.

On the level of actual national policy, the damage has been more contained, with one big exception: Both parties' standard-bearers have come out against the Trans-Pacific Partnership, the free-trade agreement negotiated by President Barack Obama.

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For Donald Trump, hostility to the TPP is at least consistent with his long-standing, wrong-headed suspicion of interaction between the United States and partners around the world.

Hillary Clinton knows better, as does her running mate, Tim Kaine, but both Democrats ditched their erstwhile support for the TPP to appease anti-trade Democrats led by Sen. Bernie Sanders, I-Vt.

The upshot is that no one who could be elected in November supports the 12-nation deal, which Obama's aides painstakingly negotiated and for which bipartisan majorities of both houses of Congress signaled support in a preliminary procedural vote last year.

The only hope for congressional approval of the agreement might be to hold a vote during the post-election lame-duck session, but given political trends, Senate Majority Leader Mitch McConnell, R-Ky., was probably right when he said last month that "the chances are pretty slim."

So it was refreshing in two ways to see Obama stick up for the proposed agreement during his joint news conference with the prime minister of Singapore, Lee Hsien Loong, on Tuesday.

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First, in sharp contrast with the tone TPP opponents in both parties have adopted, the president spoke respectfully of those who disagree with him on the issue, noting their genuine concerns about the impact on U.S. jobs of past agreements, as well as the need to incorporate labor and environmental protections in poorer trading partners abroad.

Second, Obama refused to back down on the merits of the issues, noting that other countries, not the United States, would do most of the market-opening under the TPP and challenging opponents to explain how "existing trading rules are better for issues like labor rights and environmental rights than they would be if we got TPP passed."

Beyond its economic importance, the TPP is - or would be - a pillar of future U.S. strategic relevance in the vital Asia-Pacific region and a check on Chinese influence.

It fell to Lee of Singapore to explain those high stakes.

Noting the political risks taken by leaders of other nations that agreed to the TPP, especially Prime Minister Shinzo Abe of Japan, he warned that rejection of the agreement would do serious damage to the United States' reputation abroad - "for a long time to come."

We hope Congress was listening closely to that part of the news conference.

We hope, too, that Obama was right when he remarked that "after the election is over and the dust settles, there will be more attention to the actual facts behind the deal and it won't just be a political symbol or a political football."

Both of those hopes are, as McConnell said, "slim." But slim is better than none.