With just over a month left in the regular season, the Nationals have a solid starting rotation with the best ERA in the National League. Assuming the playoffs started tomorrow, the Post Sports Live crew debates which Nationals pitcher should start Game 1. (Post Sports Live/The Washington Post)

It’s easy to say “World Series.” It’s hard as the devil to get there. So many things stand in your way. Large things. Such as Clayton Kershaw.

All players know but many fans never truly sense how tough it is to win a title in a 30-team sport or capture a pennant in a 15-team league. The odds are obvious; it’s a once-in-a-generation goal. But it can help sharpen focus and correctly calibrate expectations if there is one formidable symbol of the massive difficulty of the task — such as Kershaw, who is roughly as good as Sandy Koufax.

At times, a whole season can distill to simple questions such as, “How do you avoid this guy? If you must face him, how can you delay it as long as possible? And how can you meet him on your turf, not his?

Late Tuesday night at Dodger Stadium, the Washington Nationals lost, 4-1, and never slightly ruffled a pitcher who’s about to win a third Cy Young award in four years, something just five pitchers have done. Of them, Kershaw’s recent run is second only to Pedro Martinez in pure domination, perhaps a bit behind Greg Maddux, comparable to Koufax or Randy Johnson and better than Jim Palmer.

Like any team, the Nats have several obvious obstacles to a pennant. The Cardinals are getting healthy and have taken the National League Central lead as the Brewers fade. St. Louis isn’t nearly as strong as in ’12 and has been outscored for the season. But “St. Louis” on a jersey has bothered the Nats. The Braves, perhaps to a lesser degree, might be a tough October matchup. And a closer with a 6.11 ERA since the all-star break can be a headache.

The Post Sports Live crew debates where Matt Williams should play Ryan Zimmerman when he returns from the DL to a likely first-place team in the middle of a pennant chase. (Post Sports Live/The Washington Post)

But like a Koufax or Johnson in the past, Kershaw is the toughest task of all. How does The Claw fit into Washington’s future? As little as possible if the Nats have their way. After their meeting in L.A. and also being held scoreless for seven innings by Kershaw in May in Washington, the Nats should understand their September project perfectly: finish with a better record than the Braves to win the NL East but also beat the Dodgers for the best record in the NL.

The same “best-record” mantra should be chanted by every other NL contender. But the Nats, two games ahead of L.A. in record, have the best chance to do it. So use them to illustrate.

Oh, the Nats already understand. Their mini-epic 14-inning 8-5 win Wednesday in Chavez Ravine was one of the best marathons imaginable, with five RBI by Adam LaRoche, who didn’t enter the game until the ninth inning, yet put the Nats ahead three times — yes, three times. I went to dinner with my wife and still came back in time to see the Nats win to maintain the edge on the Angelenos for the league’s best record.

Here’s why it matters: When Kershaw pitches, the Dodgers are 19-4. When he doesn’t, they’re 59-58. With him, nobody beats ’em. Without him, anybody could.

●If the Nats finish with the league’s best record, they would meet the winner of the wild-card-vs.-wild-card game in the division series. If the Dodgers end up in that situation, then L.A. has already set up their rotation so Kershaw almost certainly will end up starting the wild-card game if that’s where they end up. If that’s the case, then the Nats would face him only once in the division series.

●If the Nats have the best record and the Dodgers win the NL West from the Giants, who trail them by two games, then L.A. would have to play the NL Central winner in the division series. Maybe the Dodgers get knocked out. Maybe the Cardinals or Brewers, with lots of right-handed punch, even beat Kershaw.

●Also, the later you meet Kershaw, the better. Any team prefers to face the Dodgers in a seven-game National League Championship Series, not a five-game division series. Why? Maybe Kershaw would have to pitch in Game 5 of the division round and thus wouldn’t be available until Game 3 of the league championship series. Even if L.A. was lucky enough to have its rotation fall in place so The Claw could pitch Game 1 of an NLCS, he would have to work on short rest to start Games 4 and 7. And Kershaw has never started a regular season game on three days’ rest and has done so only once in the playoffs. L.A. has always thought he was too valuable to risk. They owe him $193 million starting next year. Wanna gamble? How effective would he be? Well, he ain’t gonna be any better than he already is.

●Finally, if the Nats have the best record, they also would have home-field advantage if they got to a seven-game NLCS. Those Games 1 and 2 and potentially Games 6 and 7 in D.C. could carry extra weight against the Dodgers. In the four years of his current reign, Kershaw’s ERA in Chavez Ravine is 1.78. On the road it’s 2.50. That’s not much help, but it’s all you’re going to get. Take it.

Some who follow the Nats will imagine best-case scenarios that match Washington against teams they’ve often beaten, such as the Giants or Brewers, rather than the Cardinals or even Braves. That helps. But when the October picture includes a pitcher on an all-time great historic run, he matters most of all.

Look at the postseason records of the six pitchers who had (or will soon have) three (or four) Cy Young awards in a four-year span. Some of them had playoff problems in other parts of their careers. But during those dominant years, none had a postseason ERA worse than Maddux (3.38), and all six of them combined to pitch 225 innings in their Multi-Cy Period with an ERA of 2.32.

The Dodgers certainly know it. They already have arranged their rotation so Kershaw will start: (1) Sept. 28, the final Sunday of the regular season if they desperately need a win; or (2) in a wild-card game Sept. 30 if they can’t hold NL West lead; or (3) in Game 1 of a division series so Kershaw can also pitch in a potential winner-take-all Game 5.

The optimism of making the playoffs in any sport can make it difficult to spot the real stature of your main foe. That won’t be a problem for the Nationals. Or, after Tuesday night, for their fans. Bryce Harper hit a 400-foot bomb off Kershaw after he already had the game tucked safely at 4-0. That’s a confidence booster for a 21-year-old. Otherwise for the Nats, like so many others, there was only silence.

Kershaw is the universal obstacle. Your best hope is to let somebody else beat the Dodgers first or battle Kershaw in a seven-game series in which you have home-field advantage. Even that’s a brute.

The goal for every NL contender this month will be the same: finish with more wins than L.A. But just two teams have a realistic chance: the Giants and the Nationals. Their work is cut out for them.

For more by Thomas Boswell, visit washingtonpost.com/boswell.