CNN  — 

The 2020 election, as you may have heard, is 29 days away. And the Republican Senate majority, as you may have also heard, is in deep trouble.

But something that happened on Monday that has absolutely nothing to do with the 2020 election has dire consequences for the long-term hopes of the Senate GOP.

What happened is that Sen. Pat Toomey, a Pennsylvania Republican, announced that he will not run for another term in 2022

That is a BIG deal for Republicans. Why? Because Toomey, who was first elected in 2010 and then reelected in 2016, might be the only Republican who could have won the state in those two elections – especially the latter race.  And he may well be the only GOPer who could have held the seat for Republicans in 2022.

Now Republicans will have to contend with an open seat in a state where, with the exception of Donald Trump in 2016, no GOP presidential nominee has carried since 1988.

And Toomey’s announcement is simply the latest piece of bad news for Republicans, who will either be clinging to their Senate majority in 2022 or trying to win back what they lost in 2020.

North Carolina Republican Sen. Richard Burr announced in the summer of 2016 that he would not run again for office when his term ran out in 2022, creating another open seat in a swing state for the GOP to defend.

Pull back from individual races, and the picture becomes even worse for Republicans. They have to defend, at present, 22 seats to just 12 for Democrats. (That could change by two seats if Sens. Martha McSally of Arizona and Kelly Loeffler of Georgia, both Republicans appointed to their seats, are defeated this fall.)

In addition to the Toomey and Burr open seats, Republicans will have to defend GOP incumbents in Florida, Iowa (if Sen. Chuck Grassley retires), Ohio and Wisconsin – all swing states at the moment. By contrast, Democrats’ only obvious points of vulnerability are in Colorado (Sen. Michael Bennet) and Nevada (Sen. Catherine Cortez Masto).

That math – even if Toomey ran for a third term – was always going to make it tough for Republicans come 2022. But with Toomey now confirmed to be on the sidelines, the math back to the majority (or to stay narrowly in it) come three Novembers from now is that much tougher.

The Point: Focus on 2020 for now. But remember that on November 4, the 2022 election begins. And right now, Republicans are off on the wrong foot.