It’s a new year — happy! happy! — and being even-numbered that means elections across the country.

The political stakes, befitting the bigger-means-better Age of Trump, are considerably higher than usual.

For the first time in years, control of the House is seriously in play and, with it, the prospects for the latter half of Trump’s presidential term, which could bolster his record for reelection in 2020 or prove a death march through a slough of subpoenas and congressional torment.

Control of the Senate is a longer shot for Democrats, but also within the realm of possibility — especially after last month’s upset victory in Alabama.

Not least, there will be 36 gubernatorial races in 2018. In many states the winner will oversee the once-a-decade redrawing of congressional boundaries, which will go a considerable way toward determining control of the House, not just for one election cycle but well into the 2020s.

Let’s start with the House.

OK. There are 435 seats. Each will be on the ballot Nov. 6. To gain control, which they lost in 2010, Democrats need to win at least 24 seats held by Republicans.

What’s the chance of that?

Right now it looks pretty darned good. Midterm elections — so called because they fall at the midpoint of a president’s four-year term — tend to be a referendum on the incumbent, and that favors the opposition party because angry or unhappy voters are typically more inclined to turn out than contented voters.

Hmm. Is that some kind of fake news?

Actually, there’s plenty of history to support that assertion. Going back to 1862, the president’s party has averaged a loss of 32 seats in midterm elections. In modern times, the president’s party has lost seats in 18 of the last 20 midterms, with an average loss of 33 seats.

Elections aren’t based on history. What about the current environment?

That’s also shaping up well for Democrats. Polls have found party voters expressing far more interest in the midterm than Republicans, which is usually a sign of increased turnout. Also, on the so-called generic ballot question — which party would you rather see control Congress? — Democrats are running significantly ahead of the GOP. That’s another positive sign for them.

Finally, Democratic turnout in several special elections in 2017 ran considerably higher than expected — even in contests the party lost — which is another reason for Democratic optimism come November.

So that’s it for Republican Speaker Paul D. Ryan?

Not necessarily. There’s an old saying: (Fill in the blank) is a lifetime in politics. But we won’t trot out that tired cliche. Suffice to say it’s a long way to November.

Anything to watch in the meantime?

There’s a special election in late March to fill a vacant House seat in southwestern Pennsylvania. It’s strongly pro-Trump country — he carried the district by nearly 20 percentage points — but after the shocker in Alabama, Democrats believe they may have a chance at another upset. If so, you’ll start hearing the W-wordwith increased frequency.

“W” as in Wawa?

No, that’s a chain of East Coast convenience stores. “W” as in wave.

How about the Senate?

There are 34 seats at stake in November, or just over a third of the 100-member body. Republicans will hold a 51-49 advantage once Democrat Doug Jones is sworn in Wednesday as Alabama’s new senator. That means Democrats need a gain of just two seats to take control.

So they have an even better shot at a Senate majority than winning control of the House?

Actually, no.

Huh?

Of the 34 seats, Democrats will have to defend 26, compared with just eight for Republicans. And of those 26, 10 are in states that Trump carried in 2016. So to prevail, Democrats will have to hold onto every seat they have, plus two held by independents who vote with the party. Then they need to pick up at least two Republican-held seats. That’s a pretty tall order.

Indeed.

Their best shot appears to be in Arizona, where GOP Sen. Jeff Flake is stepping down, and Nevada, where Republican Dean Heller has the distinction of being the only Republican senator up for election in 2018 in a state won by Hillary Clinton. But in a wave year, other states could come into play.

And those governors’ races?

There will 36 gubernatorial elections across the country, in big states such as California, Texas, New York and Florida. Obviously, the winner will matter a lot to the folks living in those three dozen states. But the results will also have national import, owing to redistricting.

Do tell.

Every 10 years, after the latest census, the 435 House seats are reapportioned to reflect population changes across the country. In most states, it is then up to legislators to draw new congressional districts lines, subject to gubernatorial veto.

The way those lines are drawn can go a long way toward determining which party wins each seat.

After the 2010 census, the Republicans used their upper hand in statehouses to diminish Democratic strength across the country, allowing the GOP to keep a firm grip on the House throughout the decade.

In 2016, for instance, Republicans won 50.6% of the congressional vote nationwide but 55.4% of House seats, or 21 “extra” seats, according to an analysis by the Brookings Institution.

When does the next census take place?

In 2020.

That’s a lifetime in politics!

Please.

mark.barabak @latimes.com