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

As Meredith alluded to, the GOP primary in the 5th District is competitive today after Spartz decided to seek reelection, but only after a Hamlet rendition of "to run or not to run."

In February 2023, Spartz surprised the political world by announcing that not only would she not run for Indiana's open Senate seat, she also wouldn't seek reelection. She then repeatedly flip-flopped on whether she might reconsider her decision before announcing in February that she would indeed seek reelection, just days before the filing deadline. Spartz's decision upset the plans of the many GOP contenders who'd entered the race in the meantime — 11 candidates (including Spartz) are on the primary ballot.

However, state Rep. Chuck Goodrich looks like a real threat to Spartz. The CEO of an electrical contracting company, Goodrich has self-funded heavily — $4.6 million of the $5.5 million he'd raised as of April 17 — to give himself a significant financial advantage over Spartz, who had only raised $581,000 after barely fundraising throughout 2023. Even with the money she already had in the bank, Spartz has been outspent $4.1 million to $2 million by Goodrich.

Goodrich has emphasized his America First views and attacked Spartz, most notably by casting her as overly supportive of Ukraine in its war against Russia. Spartz is Ukrainian American, and Goodrich has claimed she's been "putting Ukraine first" while using an image of Spartz with Biden after the passage of Ukraine military aid in 2022. However, Spartz's record is more nuanced: She has been critical of Ukrainian President Volodymyr Zelenskyy and opposed the most recent round of Ukraine aid that Congress passed in April.

Yet Goodrich's attacks may be working: A late March poll for his campaign by pollster Mark It Red found him almost running even with her, trailing just 33 percent to 30 percent — a change from earlier polls that gave the incumbent a larger lead.

—Geoffrey Skelley, 538