Update: A whopping 91 percent of Tempe voters agreed to pass Proposition 403 Tuesday night. Your move, Arizona Legislature.

Our orginal story begins here:

Today, Tempe residents will vote on whether to amend the city's charter to curb the influence of so-called "dark money" in local elections.

Meanwhile, a bill that would prevent cities and towns from doing exactly that is progressing through the state Legislature.

Proposition 403, the Tempe ballot measure, would require groups spending more than $1,000 in local elections to disclose the names of their donors. Let's say, for instance, that you're a developer and you want to help defeat a city council member who's voted against several of your projects. But you don't want it to be obvious.

Under current law, your company can donate as much money as it wants to a nonprofit, even one that's been formed explicitly for that purpose. That organization (let's call it Coalition for a Better Tempe) spends $5,000 on mailers and TV ads attacking the city council member, and promoting his or her opponent. Voters will know that the Coalition for a Better Tempe paid for those ads, but they won't know that Rick T. Developer was the original source of the money.

Under Tempe's proposed ordinance, that would change. The Coalition for a Better Tempe would have to disclose exactly where its funding comes from, and that information would be made publicly available to voters. Phoenix is also considering introducing a similar measure, which would likely go on the ballot this fall.

Whether either city would actually be able to enforce those laws is an open question. Last month, the Arizona House of Representatives passed House Bill 2153, which would block local governments from enacting legislation that requires nonprofits to disclose the source of their funding. In other words, exactly what Tempe (and now Phoenix) is trying to do.

The bill was introduced by Vince Leach, a Republican from Tucson, and is backed by the Goldwater Institute, which has argued that maintaining donor privacy is essential for protecting free speech. Supporters argue that publicizing the identity of donors could have a chilling effect, and result in threats and intimidation.

Opponents argue that's not likely to happen. They often cite a quote from late Supreme Court Justice Antonin Scalia about how running a democracy requires "civic courage" and dealing with angry phone calls now and again.

Leach's bill is currently awaiting a committee hearing in the Senate. Given that it has near-unanimous support from Republicans, it will probably pass there, too, and become yet another example of how Arizona's legislature routinely prevents cities from doing anything remotely progressive.

But that won't necessarily mean that Tempe's dark money ordinance is dead.

As Tom Collins, the executive director of the Clean Elections commission, recently pointed out on Twitter, there's a legal precedent granting charter cities (such as Tempe) autonomy when it comes to certain aspects of local elections. So rather than being doomed from the start, the ballot measure may end up leading to a lawsuit.

TL;DR: If you live in Tempe and want more transparency in local elections, it's still worth showing up and voting today.