The midterm elections in the United States were initially assumed to be a foregone conclusion for Republicans, as President Joe Biden's approval ratings plunged in the face of increasing inflation, record migrant arrivals, and escalating violent crime.

With a month to go, Democrats are betting on a much closer contest, thanks to a run of legislative successes, lower gas prices, and the nomination of a slate of Trumpist candidates who have been struggling in winnable seats.

The biennial midterm elections are not as well-publicized as presidential elections, but they are crucial in determining whose party controls Congress - and hence the authority to advance or obstruct the president's agenda.

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Every seat in the House of Representatives (the lower house) is up for election, as is one-third of the Senate.

The upper house, with its statewide constituency and six-year terms, is considered more powerful and distinguished, and Democrats control it thanks to Vice President Kamala Harris' tie-breaking vote.

Senators are the only members of Congress who have the authority to approve treaties, try House-impeached officials, and confirm Cabinet secretaries, ambassadors, and federal judges.

At least eight of the 35 Senate races are considered competitive, but control of the chamber will almost surely be decided by four key states.

Pennsylvania 

According to recent polling, Democrat John Fetterman's huge advantage over Republican celebrity doctor Mehmet Oz has all but vanished, turning the election into a margin-of-error squabble.

The two are competing for the seat of a retiring Republican, which remains the Democrats' top aim for flipping a seat.

Most September surveys showed Fetterman with a two to a five-point lead, down from an average of nine points in August.

Democrats have painted Oz as an opportunistic New Jersey carpetbagger with shaky local ties and a penchant for gaffes that show he is out of touch.

Wisconsin 

In Wisconsin, Republican Senator Ron Johnson battled during the summer, but moved ahead of Democratic rival Mandela Barnes in mid-September and is now up by three points in a poll average of the last dozen.

According to the most recent Fox News survey, 44% of Wisconsin voters believe Barnes' political ideas are "too extreme," compared to 43% supporting Johnson. Notably, Barnes's figure was 14 points higher than a month earlier. 

Nevada 

In Nevada, Republican candidate Adam Laxalt leads Democratic Senator Catherine Cortez Masto by just two points, according to RealClearPolitics' polling average.

Democratic strategists have raised concerns about turnout, with many Latinos vowing to boycott the election despite Cortez Masto being the first Latina elected to the United States Senate. "It's what's keeping me up at night," Melissa Morales, president of the pro-Cortez Masto Somos PAC, told NBC.

no really, what are the differences between #Republicans and #Democrats?

Read @BenjaminNorton's latest article: "Biden says Latin America is US 'front yard’, Trump says 'backyard' - Pick your flavor of neocolonialism":https://t.co/QHAnz74vf0 pic.twitter.com/r6BiCi1B8i

— Al Mayadeen English (@MayadeenEnglish) January 24, 2022

"What I'm looking at is: Do Latinos actually turn out to vote this year? If we see the high turnout, we win in Nevada."

Laxalt, who ran unsuccessfully for governor in 2018, has claimed that a struggling economy, rampant crime, and sky-high prices are reducing Latino excitement for Democrats.

Georgia 

In Georgia, Republican contender Herschel Walker appeared to be the GOP's best shot to defeat incumbent rookie Democrat and pastor Raphael Warnock.

Walker's name recognition as a former football star has kept him in the race despite a string of gaffes, and he trails Warnock by four points in the most recent Fox News survey.

Georgia's electorate is more vehemently political than those of other battleground states, and the race has been focused on increasing turnout rather than winning over swing votes.

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Warnock has prioritized lowering prescription drug costs, tackling climate change, and assisting in the restoration of abortion rights.

"Senate Republicans' plan to ban abortion nationwide is on the ballot this November -- and we are ensuring that it remains front and center for voters," the Democratic Senatorial Campaign Committee said.

Walker has focused on the economy and anti-abortion activism. However, the anti-abortion hardliner has been accused of paying for a girlfriend's pregnancy termination in 2009, as well as lying about the number of children he has and has worked in law enforcement.

According to Stephen Marche for The Guardian in January, the political problems of the US today are both "structural and immediate."

Marche reminds us how at the start of the first civil war, the most brilliant citizens of the US failed to expect it and felt it was not imminent enough until Confederate forces bombarded Fort Sumter, quoting Henry Adams as saying "not one man in America wanted the civil war or expected or intended it."

The writer argues that the US is yet again on the verge of civil war, noting how its political system has become overtaken with rage, the legal system becoming increasingly untrustworthy, and Congress approval rates being at 20%. He notes that militias within the country are training and arming themselves for the demise of the nation. 

Capitol police have reported an increase in threats by 107%.