Apparently, President Donald Trump believed he could score some political points by releasing the transcript of a July telephone call between himself and Ukrainian President Volodymyr Zelenskiy. Whether that is true remains to be seen.

But one thing is obvious: Partisan politics has become such a take-no-prisoners affair in the United States that it threatens to affect our foreign policy adversely, under this president and his successors.

Trump is being accused by Democrat leaders of abusing his office by asking Zelenskiy to take action in Ukraine that could harm former Vice President Joe Biden’s campaign for president. House of Representatives Speaker Nancy Pelosi, D-California, sees so much political promise in the affair that she has launched an impeachment inquiry against Trump.

Much of the matter centers on that one phone call. Under pressure from Democrats, the White House released a transcript of it last week.

Did it need to be made public? No. Representatives of both parties could have examined it, agreed on its contents, perhaps released one or two sentences and kept the rest under wraps. Past practice under both Democratic and Republican presidents has been to keep leader-to-leader conversations secret, for various legitimate national security reasons.

At the top of the list is the importance of foreign officials, whether they are U.S. allies or enemies, knowing they can speak confidentially with our presidents. That leaves them free to make comments, requests, even promises they know would not play well with their constituents.

That works both ways, of course, as the Trump-Zelenskiy discussion makes clear.

Now we may be entering a period in which foreign leaders hesitate to discuss sensitive issues with Trump, for fear they — and their own political enemies — will read all about it within days, weeks or months, because of U.S. political turmoil.

Such reluctance would be dangerous, because it could close “back-channel” routes through which critical diplomatic issues have been handled many times in the past.

This is not just about Trump. It is about every president’s ability to do the job to which he or she is elected.