Monday afternoon the New York Times published an open letter from 50 foreign policy hands who had served in Republican administrations pledging to oppose Donald Trump. The letter, which you can read at the end of this post, suggests Trump "would be the most reckless president in American history."

This, as with many things in this election cycle, is basically unprecedented: Foreign policy professions like these folks are usually angling for a job with their party’s nominee, not publicly condemning him as a threat to national security. Yet this letter goes beyond the normal weird of 2016 and into some pretty revealing territory.

In just a few short pages, the letter reveals some of the fundamental dynamics at work in the GOP in the age of Trump.

First, it’s worth taking a quick look at the signatories to the letter. It’s a pretty impressive array of foreign policy officials, including well-regarded scholar-practitioners like Princeton’s Aaron Friedberg and Duke’s Peter Feaver. These are the brightest minds in foreign policy who still call themselves Republicans, give or take a few names.

But, at the same time, none of these people are all that influential. The Republican foreign policy officials that really matter — your former secretaries of state/Defense and National Security advisers — aren’t on the list. No Dick Cheney, no Donald Rumsfeld, no Condoleezza Rice, no Stephen Hadley, no James Baker.

This mirrors the dynamics in the broader Republican Party. While you’ve seen mass defections among conservative-leaning think tankers, pundits, and experts, the leading officials in the GOP are either supporting Trump (Paul Ryan, Reince Priebus) or refusing to publicly condemn him (George W. Bush, George H.W. Bush). Ted Cruz is perhaps the biggest exception, and his favorability among Republicans has collapsed as a result.

This is a big reason Trump can maintain his hold on the GOP. Most Republican voters have no idea who the signatories to this letter are. They command a handful of votes combined, made up mostly of their friends and family. The people who really matter, the top level officials with big public profiles and deep fundraising networks, have refused to mount a serious effort to distance the party from Trump.

At the same time, though, letters like this might actually matter.

Trump is in desperate need of serious policy advisers. His foreign policy team is full of marginalized Russian sycophants. His economic advisory team has more white guys named Steve than it does actual holders of economics PhDs. Yet Trump’s bizarre policy instincts and his loose-cannon approach has alienated the people who could make up a more serious team — the kind of people who signed today’s letter.

This is part of why every Trump attempt to reboot and talk seriously about policy is riddled with errors and unnecessary controversy. Not only does Trump himself have an indifferent relationship with the truth, but the people attempting to guide him toward it tend to be the GOP’s third-stringers.

There’s also a point at which this kind of thing becomes a self-fulfilling prophecy. Trump’s current poll numbers are abysmal — a new poll has him down seven points in Georgia, a state Democrats haven’t won in a quarter century.

After a disastrous week defined by him feuding with Gold Star parents, there’s real risk of a Trump death spiral kicking in. If it looks like he can’t win, then donors might stop donating, top staff members might start applying for jobs on down-ticket races, and current Republicans running for reelection might jump ship on endorsing him. This would likely depress his poll numbers further, leading to more abandonment. It’s a cycle of doom.

This letter, an unprecedented statement of opposition inside his own party, is the kind of thing that could help strengthen the perception of a collapsing Trump. At another time, this letter wouldn’t matter even a little — a similar letter by foreign policy hands during the primary had no appreciable effect. But Trump is uniquely vulnerable right now, particularly among GOP elites. This letter could end up hurting Trump more than it seems.

READ: 50 Republican officials attack Trump as a national security threat

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