So, who is likely to win control of these chambers? They are as hard to predict as the presidency. The Republicans probably have an advantage in the Senate because the Democrats are trying to protect more incumbents in highly competitive states. And three states are complete toss-ups: rust-belt Ohio, mountain-rural Montana, and western-sunbelt Arizona. All three Republican candidates have earned the MAGA label from Trump — meaning they support his brand of America First, election-denying populism. In two of those states, Ohio and Montana, the Democratic incumbents have defied gravity in previous elections by winning in states dominated by Republican voters. It is far from clear they can pull that off again.
Over in the House, it is a somewhat different story with Democrats feeling like they have a decent shot of taking control. The seat margin favouring House Republicans gets smaller with each retirement of a disillusioned moderate Republican. Democrats and Republicans are defending roughly an equal number of toss-up seats, about ten each. Keep your eyes on California and New York. The good news for Democrats is that many toss-ups occupied by Republicans are in these two blue states with "crossover" districts (which vote for president of one party and House for the other). In an era of party polarisation, crossover districts are a vanishing breed. And Democrats certainly hope so in these districts, which will be lavished with millions in campaign funds to sway a few thousand, or maybe a few hundred, voters.
House Democrats are typically at a disadvantage because of how local districts get drawn, and this election will be no different. But the House Republicans appear to be knee-capping themselves, looking like the chaos party with a radical faction, called the Freedom Caucus, pushing to depose its leaders, block funding for Ukraine, and shut down the government by refusing to approve budgets. The current Speaker, an evangelical Republican from Louisiana, is inexperienced and holding on by his fingernails. While gerrymandered districts give a slight edge to Republicans, if the party allows its most conservative factions to push hard on issues like abortion they will suffer in the suburban districts with moderate women voters.
So, the Democrats have a decent shot at re-taking the House, even if Trump wins. But bets are off if Trump expands his lead over Biden as the election nears, which would indicate a surge in Republican voters. I don't expect that to happen. The election is likely to be a nail-biter with an evenly divided electorate staying loyal to their party, even if they don't like the candidates. And in a close election for control of each office — president, Senate, and House — there are good odds of a divided government, which means the United States may drift but won't fundamentally change its relationships with allies like Australia. That may be the best news to offer during a time of rancorous disunity in the United States.