Despite the temptation, O’Rourke should sit this one out. The Democratic presidential field is already full of plausible candidates who have his strengths. Minnesota Sen. Amy Klobuchar is arguably more electable. Vermont Sen. Bernie Sanders can also raise money from small-dollar donors and draws big crowds at rallies. Joe Biden and Klobuchar can fill out the liberal-but-not-truly-progressive ideological lane. And almost all the other top-tier candidates have more experience. O’Rourke is a good candidate with a decent shot at the nomination. But instead of running for president, he should run against Republican Sen. John Cornyn in Texas in 2020.

A Senate run would allow O’Rourke to help Democrats in one of their electoral weak points without detracting from their presidential field. Democrats have had more trouble competing in the Senate than they have on most other levels for the past couple of cycles. And that’s because the playing field is slanted against this iteration of the Democratic Party.

The Senate Map is slanted right — there are more Republican-leaning than Democratic-leaning states. (David Byler/The Washington Post)

This graphic shows that this iteration of the Republican Party has a structural advantage in the Senate. Each point is a state, and the graphic shows its partisan lean (the Republican share of the two-party vote compared with the national share) over time (in presidential elections running left to right chronologically). The graphic suggests that the median state is usually red (the black line is the median), and that roughly half of the Senate represents a state that’s more Republican than the country as a whole is.

Put in more concrete terms, Republicans could get 50 seats in the Senate if they only won every state that was at least as Republican as North Carolina was in 2016. Trump won North Carolina by four points while losing the national popular vote by two. The country as a whole is pretty evenly divided between the parties, but not all states have the same population and Republicans have a natural edge in the Senate.

The Senate isn’t going away anytime soon, and if Democrats want to win the chamber they’ll have to deal with the reality of the map. One way to do that is to find candidates who are tailored to a specific state and have a record of outperforming replacement-level Democrats there. In the past, partisanship was weaker and Democrats could win many red states by running moderates and blue dogs. It’s tougher for Democrats to win red states (or Republicans to win blue states) in our modern, polarized world, but a certain Robert Francis O’Rourke almost pulled it off in Texas in 2018. So if Democrats want to compete for the Texas seat in 2020, Beto is the obvious choice.

The odds would be against O’Rourke in that race. Texas is a very red state, and there’s a solid chance that the national mood in 2020 won’t be as good for Democrats as it was in 2018. And other red-state Democratic Senate candidates haven’t fared well recently. Phil Bredesen, Kay Hagan, Mark Begich, Jason Kander, Mary Landrieu, Mark Pryor, Ted Strickland, Heidi Heitkamp, Joe Donnelly, Claire McCaskill, and, well, Beto O’Rourke all recent lost Senate races. But Joe Manchin, Sherrod Brown and Jon Tester all managed to win in unfriendly territory in 2018, so it’s not impossible. O’Rourke would start as a serious underdog, but he has a better chance than the average Texas Democrat would. And both parties should be willing to roll the dice on relative long shots when something as important as the Senate is at stake.

He should take the leap for Senate. If he wins in Texas, he can build a long, potentially very successful political career. If he fails, he’ll probably lose his golden-boy status but he’ll have helped his party build strength in a state where they want to be competitive. He could try to run for both at the same time, but I don’t know that Texas Democrats are going to want to share their Senate candidate with 49 other states. And he could run only for president and swear off all other offices. If he does that, he really could win the nomination and beat Trump.

But the more likely outcome is that he loses the primaries and, unless he gets picked as someone’s running mate, has nowhere to go from there. O’Rourke is far from the favorite in both the Senate and presidential races. But if he’s a team player, he’ll pick the Senate race — which would help his party more than a long-shot White House run.