Democrats are failing across the board. All signs point to a red wave on Election Day.

In 2016, I thought Hillary Clinton would win the presidency until late on election night. I was on live TV when Michigan, Pennsylvania and Wisconsin began to tilt red, and the shock became visible on the faces of the anchors and the crew in the studio. A Donald Trump victory wasn't in the script.

In my defense, few in the chattering classes foresaw as Election Day approached what voters were about to wrought.

Ever since, I've declined to make predictions about who will or won't win an election. And I don't really trust anyone who claims they can forecast with any certainty what voters will decide in a midterm or presidential election.

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Biden's poll numbers drag down Democratic candidates

That said, it is possible to read the trends ahead of an election to get a sense of what may happen. Let me stress the word may. And several important trends are leaning, in some cases quite heavily, in favor of Republicans. Let's look at seven key indicators:

►Joe Biden is unpopular. More than 54% of Americans, according to the Real Clear Politics polling average, hold an unfavorable opinion of the president. Biden's unfavorable ratings don't mean much in Democratic citadels like California or New York, but they matter a great deal in Georgia, Ohio and Pennsylvania, where control of the Senate will be determined.

Consider this take from New York Times progressive writer Frank Bruni about last week's Herschel Walker-Raphael Warnock Senate debate in Georgia: "Rather than Warnock trying to make Walker answer for his alliance with the former president (Trump), Walker insisted that Warnock defend his with the current one – a dynamic that doesn’t exactly track with media coverage of the midterms. We keep wondering how much Trump will wound Republican candidates. Warnock seemed plenty worried about how much Biden would wound him."

Do political debates even matter?: Was Ryan or Vance, Walker or Warnock tougher? Who cares? Political debates are overrated.

►Inflation remains out of control. The cost of everything from gas to grapes has shot up at the fastest pace in 40 years. A friend who runs an urban nonprofit recently told me his organization is asking the public to donate deodorant, soap, shampoo and toothpaste – items not covered by food stamps – because the families they serve can no longer afford such necessities. The pain of runaway inflation is felt in all sorts of humbling and frustrating ways. And voters are most likely to vent their anger at the party in control of Congress and the White House.

Mortgage and auto loan rates rise, so do crime rates

►Interest rates also are soaring. To slow inflation, the Federal Reserve has been forced to aggressively increase interest rates, which for the American public means the cost of buying a home or a car or paying down credit card debt is substantially more expensive now than at the start of 2022. It's to the point that I'm starting to have flashbacks to 1980, when the misery index was a topic of discussion in homes across America. Ask Jimmy "I lost 45 states" Carter how that worked out for him and his party.

The campaign ads are vicious: Do midterm candidates really hate each other?

►Crime is on the rise. Violent crime increased more than 4% in the first half of this year – and that's on top of already high crime rates from previous years. A Politico/Morning Consult poll this month found that 60% of voters said crime would be a major factor in determining which candidates they'd support in November. Not all those voters will go for the GOP, but it's Republicans who are hammering their Democratic opponents on the increase in crime in campaigns across the country, in part because it was progressives who championed "defund the police" and, fairly or not, Democrats are still associated with that deeply unpopular idea.

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Polls could be missing Republican voters, and history is on the side of GOP

►Economic issues overshadow abortion rights. Democrats had hoped that the Supreme Court decision to overturn Roe v. Wade in June would lead to a strong voter backlash. That could happen, but polls increasingly indicate that economic issues will drive voters' decisions. A new Times/Siena College poll, for example, found that the economy and inflation were the only issues that more than 10% of likely voters cited as the most important issue facing the nation. The same poll found that likely voters favor Republican congressional candidates over Democrats 49% to 45%.

Republican women are finally on the rise: Will they reshape the GOP?

►Polls may underestimate Republican support. The pollsters I've worked with over the years are smart professionals who take their craft seriously. They want to get the numbers right – and have strong financial incentives to do so. Even so, pollsters badly undercounted Republican voters ahead of the 2016 and 2020 elections, and there's reason to think it could happen again this year. Some media outlets such as Real Clear Politics are trying to adjust for a possible undercount of Republican voters this year based on previous election results. That's tricky at best. But there is a common perception that the polls are inaccurate, and not in Democrats' favor.

►The party in power pays. It's an old story, but one that's still relevant – the party that holds the White House almost always loses congressional seats in a midterm election. And Democrats already are working with small margins given the 50-50 split in the Senate and only an eight seat advantage in the House.

History, the economy and other trends are working against Democrats. Will that result in a surging red tide come November? Probably.

But I don't make predictions.

Tim Swarens is deputy opinion editor for USA TODAY.

More from Tim Swarens:

Republicans must move past Trump for sake of the party's future – and the nation's

Why are Republicans angry? Progressives are good at poking the elephant.

Are we trying to destroy America? From Tucker to Trump, we're doing a good job of it.

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This article originally appeared on USA TODAY: Inflation, economy help GOP gain momentum as midterms approach