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

In the safely Republican 6th District, Rep. Greg Pence — who, like his brother Mike, is conservative but not angry about it — is stepping aside, and it's very much an open question whether he'll be replaced by a moderate or a hardliner.

Former Indianapolis City-County Councilor Jefferson Shreve, the owner of a successful storage company, is the top fundraiser in the GOP primary thanks to a $4.5 million loan to his own campaign — more than his six opponents have raised combined. But wealthy state Rep. Mike Speedy has also loaned himself $1.3 million and he's using it to remind voters of the moderate positions, like supporting gun control, that Shreve took last year during his failed bid for mayor of Indianapolis (a significantly bluer constituency than the 6th District). To underscore the ideological fault lines of the primary: Shreve has the endorsement of the U.S. Chamber of Commerce, while Speedy is backed by the tea party group Americans for Prosperity and Susan B. Anthony Pro-Life America.

No other active candidate in the race has raised more than $200,000 except businessman Jamison Carrier, who raised the most from actual donors ($115,000) in addition to a $750,000 self-loan. There's a chance that Carrier sneaks up the middle between the two front-runners, as he's the only one of the three from a part of the district that's not Indianapolis, which accounted for just 23 percent of the Trump vote in the district in 2020, according to Daily Kos Elections. There's no polling here, though, so it's hard to know whether Carrier's geographic advantage will erase Shreve's and Speedy's financial edge.

—Nathaniel Rakich, 538