Happy primary day, Hoosiers! Indiana is easily forgotten on the primary calendar, sandwiched as it is between sexier states like Pennsylvania and Maryland (don't look at me like that — have you seen that flag?). But if you care about how well Congress functions, you'll want to pay attention to today's primaries, even if you don't watch "Stranger Things" and "Parks and Rec" on repeat.

As my colleagues recently so beautifully illustrated, there are several parties within the parties in Congress. On the Republican side, there are pragmatists who fall in line with party leadership — and then there are obstructionists who tend to make life harder for them.

This year, there are three open House seats in Indiana that could send either type of representative to Congress. And because these seats are safely Republican, today's contests, not November's, will effectively determine that. Elsewhere in the state, Rep. Victoria Spartz — the Hamlet from Hamilton County — could be the second incumbent representative of the cycle to lose reelection, and GOP primary voters will also choose who will likely become the next chief executive of this state of nearly 7 million people. So yeah, the stakes are high!

We won't have to wait long to find out the winners: Polls close in most of Indiana (the parts in the Eastern time zone) at 6 p.m. Eastern, with the parts of the state in the Central time zone following suit at 7 p.m. Eastern. Follow along with us for the next few hours, won't you?

—Nathaniel Rakich, 538

While ABC News is not yet reporting a projection in the tight race for the GOP nomination in Indiana’s 3rd District, the AP has made a call: They are saying that Stutzman will be the winner. That would make the 3rd District today’s only win for the insurgent wing of the Republican Party: Stutzman was an OG tea partier who helped force out former Speaker John Boehner in 2014.

—Nathaniel Rakich, 538