On Friday morning, President Trump unleashed a series of tweets blasting the FBI and the Department of Justice for not investigating Hillary Clinton and the Democrats.

The tweets provoked instant condemnation from Trump's critics, who highlighted the troubling implications of the president teeing off on law enforcement officials that are supposed to operate independently, urging them to go after political opponents. By and large, I am sympathetic to this criticism. However, viewed another way, Trump's tweets actually should be comforting.

When Trump was elected, many of us feared what would happen when the power of the presidency was put into the hands of somebody with a lack of impulse control, thin grasp of the limits on executive power, praise for international strongmen, and a background as a CEO who typically got his way. The big question for many of us Trump critics was whether the United States's institutions were strong enough to resist Trump's authoritarian streak. So far, the answer has largely been yes, and the fact that Trump is left tweeting into the wind in frustration like the rest of us, because he can't get law enforcement to behave in his preferred way, is evidence of that.

Sure, Trump fired the director of the FBI. And sure, he appointed a loyal ally who was a key part of his campaign and biggest early endorser, to run the Department of Justice. But even after taking those actions, he hasn't been able to get those agencies to behave in his preferred manner.

In countries with weaker democratic institutions, leaders do more than take to social media to vent their frustrations with law enforcement — they simply jail political dissidents. In Russia, for instance, Alexei Navalny, a leading critic of Russian President Vladimir Putin, has been jailed three times this year alone for holding rallies critical of the government.

It's true that we're still relatively early in the Trump administration and things can get worse. Also, there are plenty of steps Trump could take that would stop short of Putin and still be alarming.

That said, it's important to remember that when Trump complains about law enforcement on Twitter, it isn't a sign of strength, but of weakness. It's a testament to the limits that our Constitution places on presidential power.