(CNN) — The 2022 midterms have arrived, as voters across the nation decide who will set the agenda in Washington and in statehouses across the country for the next two years -- and who will set the ground rules for 2024.

The House and Senate, where Democrats currently hold narrow majorities, are up for grabs. Republicans need net gains of just one seat to win the Senate and five seats to win the House.

The governor's offices -- and control of the election machinery -- are also on the line in a slate of states that are poised to play crucial roles in the next presidential race.

Voters will render final judgments on the trends that have dominated the 2022 political environment. Among them: Is a Democratic backlash over the Supreme Court's reversal of Roe v. Wade brewing? Can the GOP build on their 2020 gains among Latino voters and remake the battleground map in the process?

And will dissatisfaction with President Joe Biden and big-picture challenges like inflation dominate everything else, sweeping Republicans into power -- or will voters reject some GOP candidates, delivering Democrats some surprising victories?

Here are seven things to watch in Tuesday's midterm elections:

Who will control the House?

Of all the major storylines on Tuesday evening, this is one that few Democrats dispute: It is unlikely the party will control the legislative chamber come January.

Given Republicans only need a net gain of five seats to take the majority, the odds of the GOP taking back the House are high. The party is on offense in House race across the country, but most notably in districts Biden won handily just two years ago, including once seemingly solid blue districts in Rhode Island, New York and Oregon.

"If you knew nothing else other than there would be generationally high inflation this cycle, you'd be able to predict that the party in power was going to have a tough election night," said Tyler Law, a Democratic operative who worked as a spokesperson for the Democratic Congressional Campaign Committee in 2018. "That certainly doesn't mean Democrats won't exceed expectations. But we can't ignore the macro trends that have shaped the cycle."

The polling also backs up Republican confidence. In a CNN poll released this month, Republicans topped Democrats on a generic ballot question asking voters which party's candidate they would support in their own House district by 51% to 47% among likely voters, narrowly outside the poll's margin of sampling error. The generic ballot question is often a leading indicator of which party will have a better midterm night.

"Those chances would be zero," Doug Heye, a longtime Republican strategist and former communications director for the Republican National Committee, said of the chances his party doesn't control the House in January. "If Republicans only win seven seats, it would be a letdown, but they would still have the House."

Who will control the Senate?

If control of the House feels like more of an unavoidable loss for Democrats, control of the currently evenly divided Senate offers a surprising bright spot for the party -- aided by voters harboring unfavorable feelings about Republican candidates while also disapproving of Biden's job performance.

The most vulnerable Democratic incumbents are on the ballot are in Nevada, New Hampshire, Arizona and Georgia, where polls show each of those races are tight.

The party is on offense in Pennsylvania and Wisconsin, two states Biden won just two years ago. Although party operatives have grown less confident in their chances of unseating Republican Sen. Ron Johnson in Wisconsin, the same operatives remain confident in Democrat John Fetterman's chances of defeating Republican Mehmet Oz in Pennsylvania open Senate race. The party has also benefited from Republicans being required to spend millions defending candidates in Ohio and North Carolina, two states Biden lost that have seen stronger-than-expected campaigns by Democrats Tim Ryan and Cheri Beasley.

The outcome of these races hinge on whether enough voters go to the polls seeking to punish the party in power or if the ill-will they have towards unpopular Republican candidates is able to overcome the economic concerns.

To both Republicans and Democrats operatives, the fight for the Senate likely rests on which party wins the hotly contested and at-times divisive Pennsylvania Senate race, a contentious race that has seen nearly $160 million in ad spending since Labor Day, the most of any other Senate contest.

Election deniers in key swing states

Contests in Arizona, Michigan, Pennsylvania and several other states could have key ramifications for the 2024 presidential race, as Republicans who have parroted former President Donald Trump's lies about widespread voter fraud seek to take charge of those swing states' election machinery.

The outcomes in those states could have dramatic consequences in 2024, with Trump on the verge of another presidential bid and candidates in crucial swing states seeking positions that they could attempt to use to undercut voters' will.

The Republican nominees for governor in those three states have all questioned the legitimacy of the 2020 presidential race. Arizona's Kari Lake is one of the most vocal proponents of Trump's election lies. Pennsylvania's Doug Mastriano, a state senator, bussed people to Trump's January 6, 2021, rally that preceded the attack on the US Capitol. In Michigan, a GOP ticket of election deniers includes Matt DePerno, an attorney general nominee who is connected to a series of potential voting machine breaches.

In Wisconsin, Democratic Gov. Tony Evers has positioned himself as the last line of defense against a GOP overhaul of voting laws that would impose new restrictions on mail-in voting, scrap the state's bipartisan election commission and more. Evers vetoed those measures in 2021, but Republican challenger Tim Michels could sign them into law. Or, if the GOP wins supermajorities in the heavily gerrymandered Assembly and Senate -- where the party already holds large majorities -- it could simply override Evers' vetoes.

Republicans have nominated 11 candidates who have rejected, questioned or tried to overturn the results of the 2020 presidential election for posts as their state's chief elections officers. Among them: In Nevada, Jim Marchant, the Republican nominee for secretary of state, ran a campaign ad questioning the legitimacy of Democratic congressional leaders' victories in heavily Democratic areas.

Will Latino voters continue rightward shift?

One of the most important questions on Tuesday -- one that could decide the outcome of a slate of key races -- is whether Republicans will build on the gains that Trump made among Latino voters two years ago.

Three House races in the heavily Hispanic Rio Grande Valley in Texas will tell part of the story. The region has historically voted Democratic, but it is also culturally conservative, and Trump narrowed Democratic margins there dramatically in 2020.

In the 15th District -- drawn to be the state's most competitive -- Monica De La Cruz is the most likely of three Latina Republican nominees to deliver her party a victory. But if the GOP can defeat two Democrats in neighboring districts -- Rep. Henry Cuellar in the neighboring 28th District, which stretches from San Antonio to Laredo, or Rep. Vicente Gonzalez in the 34th District, which includes McAllen -- it would offer a clear sign that the GOP has built on its gains in the region.

Latino voters also make up crucial portions of the electorate in Arizona and Nevada, where governor's offices and Senate seats are up for grabs. Clark County, the home of Las Vegas and historically a firewall for Democrats in the state, could offer important insight into the makeup of this year's electorate.

Another key place to watch: Miami-Dade County in Florida. Historically a Democratic stronghold -- Hillary Clinton defeated Trump there by 29 percentage points in 2016 -- Trump made massive inroads in 2020, losing to Biden by just 7 points in the county. If Republican Gov. Ron DeSantis, who lost the county by 21 points in 2018, can further chip away at that margin, or even win the county, it would signal a huge shift that could fundamentally alter the political landscape in one of the nation's most important swing states.

The impact of presidential politics

It may be a midterm election, but the impact on presidential politics will be dramatic.

That was clear over the final weekend, with the last three presidents -- one current, two former -- campaigning in Pennsylvania alone. Biden also made trips to New York, Maryland and California, among other states, while Trump spent the final week in Iowa, Florida and Ohio.

Their appearances on the campaign trail this week were both a possible foreshadowing of a 2024 rematch and a reminder of how midterm elections can impact a presidency. Although Biden told reporters in California that he believed Democrats would hold the House and pick up a seat in the Senate, Democrats back in Washington have privately acknowledged how Biden's presidency would be reshaped by a Republican controlled Congress, a lesson Trump learned in 2018 when Democrats took control of the House.

"If we lose the House and Senate, it's going to be a horrible two years," Biden said at a fundraiser on Friday. "The good news is I'll have a veto pen."

It's an argument former President Barack Obama, who stumped for candidates in Georgia, Michigan, Wisconsin, Nevada, Arizona and Pennsylvania over the last few weeks, made explicitly during his final rally in Philadelphia on Saturday.

"I can tell you from experience that midterms matter, a lot," said Obama, who lost the House of Representatives during the 2010 midterms and then the Senate in 2014. "When I was president, I got my butt whopped in midterm elections. ... I am not big on looking backwards, but sometimes I can't help imagine what it would have been like if enough people had turned out in those elections."

The wave-makers (or breakers)

The shape of Congress over the next two years could become pretty apparent within the first few hours after the polls close on the East Coast -- even if a handful of big races are too close to call.

There are a handful of House seats, in particular, that bear watching. Right at the top of the list are three in the New York City suburbs, two in Nassau County on Long Island (the 3rd and 4th Districts) and one in the Lower Hudson Valley, north of the city (17th District).

The 3rd and 4th Districts are open seat contests because the Democratic incumbents, Reps. Tom Suozzi and Kathleen Rice, decided to leave. And up in the 17th, Rep. Sean Patrick Maloney, chair of the Democratic House campaign arm, is facing a tough, well-funded challenge from Republican state Assemblyman Mike Lawler.

For Democrats, defeat in even two out of three of the contests would portend a very, very bad night. The party, both nationally and in certain states, has increasingly invested its electoral fate on the notoriously fickle suburbs. If a Republican wave is coming, the first sighting of high tides will be up and down the Atlantic seaboard.

Other seats that could telegraph things to come based on how they unfold earlier in the night -- all home to Democratic incumbents not previously thought to be in tight races -- include: New Jersey Reps. Josh Gottheimer in the 5th Congressional District, and Andy Kim in the 3rd; Rep. Jahana Hayes' 5th Congressional District in Connecticut; and Virginia Rep. Jennifer Wexton in the commonwealth's 10th Congressional District.

And then we wait

As most Americans learned two years ago, Election Day can be a misnomer. Tuesday is when voting ends. But, in many states, it's also when counting begins.

That means a lot of hotly contested races -- perhaps those contests in particular, if they're as close as expected -- could take into the wee hours or even later this week to be decided.

That's partially the nature of counting (and sometimes recounting, which could drag things out much, much longer), but it's also due to state laws that instruct poll workers how to do their jobs and, in some states, make them hold off on doing them until later in the day.

Per a helpful guide from the National Conference of State Legislatures, here are a few states everyone will be keeping close tabs on and when they start counting absentee, or mail-in, ballots:

• Arizona and Nevada, home to big races up and down the ballot, allow the counting of ballots to begin before Election Day, which should make for a quicker burst of information after polls close.

• Among the key states that only permit the counts to begin on Election Day itself, but before polls close, are: Georgia, Michigan, New Jersey, New York, North Carolina, Ohio, Oregon, Pennsylvania, Wisconsin and Texas.

• Finally, there are 16 states that don't allow counting to start until after the polls close. Notables among them include: Maine, New Hampshire, Virginia and Alaska.

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