(NewsNation) — Pivotal primary elections will be held in Iowa, California and five other states on Tuesday, as the nation trudges ever closer to deciding the makeup of a narrowly divided Congress.

Control of the Senate, which is currently divided 50-50, is a crucial priority for Democrats and Republicans. Both parties have been throwing their political weight behind candidates nationwide in an effort to turn political tides in D.C.

One of those hotly contested Senate seats in Iowa will be under the political microscope Tuesday as the Midwestern state will have all eyes on it. Meanwhile, in California, Republicans are looking to flip more House seats in their bid to control Congress.

New Jersey, Montana, New Mexico, South Dakota and Mississippi are also holding primary elections.

What to watch for in Iowa

Sen. Chuck Grassley, who is the second oldest member of Congress at 88 years old, is expected to win his primary over challenger Jim Carlin. Iowa’s Democratic primary, however, which will determine Grassley’s general election opponent, is where much of the attention will be focused.

Three candidates are vying to take on Grassley in November: former U.S. Rep. Abby Finkenauer, retired Navy Adm. Michael Franken and physician Glenn Hurst.

Finkenauer is the most intriguing possibility. In 2018, she became the second-youngest woman ever elected to the House, beating a Republican to do so. She has raised over $3 million during her Senate campaign.

However, Franken poses a significant challenge. He raised just less than $2 million during his campaign and has worked on Capitol Hill far longer than Finkenauer, having served as an aide to former Sen. Edward M. Kennedy of Massachusetts as well as working as a liaison to the Obama administration for the Department of the Navy.

What to watch for in California

There likely will not be many surprises in California, where Democratic voters outnumber Republicans 2-1, and Republicans have failed to win a statewide election since 2006.

Incumbent Sen. Alex Padilla, D-Calif., faces a handful of primary challengers, but is expected to emerge from the scrum victorious.

Republicans are hopeful, however, that problems facing California, such as crime, homelessness and inflation can help their message as they vie to pick up more House seats.

Democrats lost four House seats to Republicans in 2020, but still hold a large majority of the state’s overall delegation by a margin of 42-10 (with one seat vacant).

While it is not likely any significant political swing will happen in California, if Republicans can pick up a few more seats in the solidly blue state, it could have some noticeable ramifications in Washington.

Republican Leader Kevin McCarthy, who is from California, could unseat fellow Californian Nancy Pelosi as speaker of the House, and he expects to, if Republicans can flip the House in November.

A race for district attorney in San Francisco, where liberal Chesa Boudin is being recalled amid a spike in crime in the city, could be interesting to watch on the national level as it could indicate if Democrats are moving back toward the center on crime.

What to watch for in New Jersey

No incredible seismic shifts are expected from New Jersey’s primaries, but Republicans will be closely watching two races where candidates backed by former President Donald Trump and running as “America First Republicans” are vying to take down more moderate Republicans.

It’s been a mixed-bag for candidates who align themselves with Trump so far in primaries. He suffered embarrassing defeats in Georgia, but had surprising wins in Ohio and elsewhere.

New Jersey’s more moderate Republicans, Chris Smith and Tom Kean Jr., are expected to win their primaries, according to northjersey.com. Moderate Republicans are typically favored in New Jersey, a state that is heavily Democratic, but a win by Trump-backed Republicans could signal a major shift in the party’s direction.

What to watch for in New Mexico

New Mexico’s Tuesday primaries will largely be focused on statewide races for attorney general and a Republican nominee to challenge Democratic Gov. Michelle Lujan Grisham in November.

However, challengers for two congressional seats, one held by Democratic Rep. Melanie Stansbury and the other by Republican Rep. Yvette Herrell, will be held on Tuesday as well.

What to watch for in Mississippi

There are no Senate seats being voted on in Mississippi on Tuesday, and little action is expected in House primaries in the state that holds just four seats, three of which are controlled by incumbent Republicans who are not expected to lose their races.

What to watch for in Montana

Montana has just one House seat, held by incumbent Republican Matthew Rosendale.

That seat has not been without its fair share of drama, however. National rhetoric around voter fraud and wild conspiracies about votes being sent to Spain have made their way into Montana’s election cycle.

Extra security has been put in place at polling places in the state because of threats issued by people who believe election fraud is planned there, according to the Independent Record.

What to watch for in South Dakota

South Dakota’s primaries are not drawing much attention, even from people who live in South Dakota.

Voter turnout is expected to be low, but that does not mean there are not important races here. A Republican Senate primary between Gov. Kristi Noem and state Rep. Steve Haugaard could make political waves on Tuesday.

Expected low voter turnout still has not stopped Republicans from raising boatloads of money in the state.