You argue that 40% turnout in Alabama’s special election shows that most Americans believe “neither the Republican nor the Democratic parties are putting forth a choice that is remotely worthy of consideration.”

But there’s a much simpler explanation: most Americans don’t care about elections.

Your argument implies that more appealing candidates (or parties), who are more in touch with the electorate, would inspire many more to vote. But there’s no reason to assume that.

Here’s what turnout looked like in the last five midterms:

2014: 36.4%
2010: 40.9%
2006: 40.4%
2002: 39.5%
1998: 38.1%

Turnout for the Alabama special election was in line with those midterms. About 40% of Americans care about elections with the potential to shape Congress (as the Alabama special election did).

More Americans care about presidential elections. In presidential years, over half of eligible voters turn out — except 1996, when turnout was 49% — but it’s not much more than half.

Obama’s first election in 2008 had 58.2%, the highest turnout since 1968. That shows a presidential candidate might inspire more people to vote. But still, almost 42% didn’t bother. We’re not going to get a candidate for Senate who excites Americans as much as Obama ’08, let alone more.

In contrast to your theory that low voter turnout is caused by unappealing candidates/parties/policies, the more likely explanation is the cost of voting. It takes some effort, and the less convenient it is, the less likely people will do it (because, again, many of them don’t care).

Want to raise turnout? Enact automatic, universal registration. Give voters many options — mail-in, online, early voting, etc. — and make those options convenient. Well staffed polling places, so no one has to wait in line. Numerous polling places, so no one has to go far out of their way.

Australia has mandatory voting and gets much higher turnout than the U.S. (94% of registered voters in 2016, with only about 10% of the population unregistered, for turnout around 85%).

There’s no candidate, no party, no policy change that will get anything close to 85% of Americans to vote. Especially not in a non-presidential election. Your theory of engaged Americans evaluating the options and then declining to vote sounds nice. But the reality is a lot of them just don’t care.