For the purposes of this post, I’m not going to litigate the pros and cons of the Trans-Pacific Partnership. I just want to note that the president is heading to Asia and that he will be making a final push (particularly in Laos) for the trade agreement. And, despite all appearances, there are people who think that Congress could still conceivably have a vote and potentially pass the treaty in a lame duck session of Congress after the election.

“T.P.P. is, in many ways, seen as a litmus test for whether or not the U.S. has staying power in this region,” Benjamin J. Rhodes, the deputy national security adviser, said to reporters on Monday. “What the countries of the Asia-Pacific region want to know, particularly the Asian countries, is whether or not we can be counted on.”

Mrs. Clinton’s unyielding opposition has been particularly troubling to Asian leaders, analysts said, given that she spoke out regularly in favor of the agreement when she was secretary of state. “I oppose it now, I’ll oppose it after the election, and I’ll oppose it as president,” she said last month at a campaign rally in Michigan.

Many Asian leaders believe that Mrs. Clinton would happily carry out the T.P.P. if it were approved before her inauguration, as do some members of the Obama administration. Others believe she will reverse her position if a few elements of the pact are tweaked. But as she has dug in her heels, such a reversal is harder to contemplate.

“They are starting to realize that if it doesn’t get through in the lame duck, it will be very hard for her to pivot back to the position she had as secretary of state,” said Michael J. Green, an expert on Asia at the Center for Strategic and International Studies.

Now, I’ve never thought that the TPP has a chance in hell of passing, but I’m trying to imagine the hue and cry if it actually did.

Clinton long ago disavowed the support she gave the treaty as a loyal soldier in the Obama administration, and both Trump and Sanders have been vehement opponents. Regardless of who wins the election in November, they’ll be officially opposed to the TPP.

Under those circumstances, a lot of voters would be justified in seeing a mandate against the treaty and that it would be wrong and unfair to saddle the incoming president with implementing a policy that they ran against.

Maybe it will somehow pass anyway, but it’s hard to see how it can get the votes when it’s seen as so toxic that the presidential candidates can’t support it.

And, whatever Clinton thinks about the merits in the privacy of her own office, she would not want to begin her presidency with the left feeling betrayed and saying “I told you so.”

It’s also hard for me to envision the Republicans coming up with enough votes to overcome near-universal opposition from the Democrats. If the popularity of Trumpism with their base isn’t enough to warn them off, their aversion to working to advance Obama’s agenda and legacy will probably be enough to dissuade them.