The way David Petraeus describes U.S. foreign policy under Donald Trump is hard to quickly summarize. I guess he’s basically saying that the foreign policy establishment, including the key figures in Trump’s cabinet, is like a really sturdy ship with lots of ballast with an excellent crew. While it might be true that the captain is charting an erratic zig-zag course, there’s little danger that the ship will get lost or capsize. In fact, the basic structure and crew is so solid that it’s “immaterial” whether or not the captain is mentally ill because he is incapable of doing any lasting harm.

This is nonsense, of course. Trump is destroying America’s credibility on the world stage, and there is now statistical evidence to support this. Pew Research recently surveyed people in 37 nations, and only the people of Israel and Russia have a better opinion of Trump’s America than they had of Obama’s. In most cases, the drop-off is very large. We’re down 83 points in Sweden, for example, and 75 points in Germany and the Netherlands.

Moreover, not every impulsive, ill-informed, ill-considered decision can be corrected by Trump’s staff and the foreign policy establishment. Petraeus cites a few cases of this happening, like when Trump seemed to waffle on the two-state solution in Israel/Palestine or the One-China policy. Petraeus assured us that the failure to reassure Europe about our commitment to Article 5 of NATO has been rectified and that our Syria policy is ultimately on a sound course. But some decisions can’t be taken back.

What happens when Trump gives an order that commits us to a course of action? And, however wise our foreign policy establishment might be (and recent history calls this premise into serious question), what happens when they don’t agree with each other and a mentally ill person needs to make the final call?

Anyone who says that it’s okay to have a mentally ill captain isn’t a serious person. We’re now faced with making a decision about whether we can wait around until after North Korea has miniaturized their nuclear weapons to the point that they can place them on ICBMs before we respond. Does Trump understand what might be required of our nation if we decide to take preventive military action against Pyongyang. Does he know what will happen to Seoul and perhaps Tokyo? Does he even know what China did the last time we had a conflict on the Korean peninsula or what would be required to prevent a potentially nuclear-armed conflict with them?

Before anyone even thinks of committing us to that kind of risk, they’d have to understand all of it. They’d have to prepare for it. One reason we didn’t win in Korea the last time is because we weren’t ready for it. There are enormous diplomatic and alliance-building tasks that would be involved, and those same types of tasks will be required to settle the matter without war.

We’d also need a leader who had some credibility with the American people and with Congress. Even if Trump is mentally fit in some ways, he doesn’t have what it takes to meet these challenges. Petraeus should know this and I think he does. Why he says otherwise is anybody’s guess, but he’s not helping.

The stakes are far too high here for this kind of screwing around with the truth. People like Petraeus need to stop bullshitting us and themselves and get on board with making sure we’re prepared for what’s coming. We’ll never be prepared as long as Trump is the final decision-maker.