One can certainly understand, if not quite sympathize with, House Speaker Paul Ryan's predicament. His party has picked a presidential nominee who appears unelectable and is, with each passing day, doing untold damage to the party's reputation that may last for decades.

As John Patty explained, Ryan is trying to thread the needle between disavowing Donald Trump's worst statements and keeping his party unified to avoid a down-ballot catastrophe. Thus he has criticized Trump's comments and told fellow Republicans to follow their consciences, while still maintaining his endorsement of Trump. But Ryan's biggest failure so far is not standing up for America's democratic system of government.

As has been widely reported, during the second presidential debate Trump vowed to appoint a special prosecutor to investigate Hillary Clinton should he be elected president. He added that should he be elected, she'd go to jail, a threat he's repeated in several campaign appearances since then.

Such statements are entirely antithetical to democratic governance and the rule of law. As Joshua Tucker noted, it is authoritarian strongmen in places like Ukraine, Belarus, and Myanmar who make such campaign promises. It is, perhaps, hackneyed to refer to an idea as "un-American," but Trump running on a promise to put his opponent in jail is literally the opposite of the ideals on which the nation was founded.

Now, why are these statements worse than Trump's comments about his own sexual predations or anything else? Why would these specifically require a reaction from Ryan?

Paul Ryan is the elected leader of the most democratic branch of government. The speaker of the House has a dual mandate — he or she functions as a party leader (and is often elected on a party-line vote) but is also a constitutional officer, serving as the leader of the chamber. Sen. Mitch McConnell, as the leader of a party caucus, bears no such official responsibility to his chamber. (Joe Biden is president of the Senate.) Indeed, it is often the speaker of the House who will push back against accretions of executive power, which can lead anti-democratic outcomes.

The speaker of the House has a dual mandate — he or she functions as a party leader (and is often elected on a party-line vote) but is also a constitutional officer, serving as the leader of the chamber

But when democratic institutions themselves are under attack, does not the leader of the most democratic branch of government have some obligation to defend it? How can Ryan maintain an endorsement for a presidential candidate who has promised, repeatedly and publicly, to undermine the nation's democratic traditions?

To be sure, there has been no shortage of statements by Trump inviting condemnation by his fellow Republicans on a broad range of topics. But when democracy itself is at risk, there is no political figure better situated to stand up and defend it than the House speaker. By maintaining his endorsement for Trump, Ryan has failed at this vital task.