This is the month when House Republicans decide whether they want to march off a cliff with bands playing and flags flying.

By any rational calculation, the decision to shut down the government or impeach President Joe Biden would seriously imperil the GOP’s chances of retaining its slender House majority in 2024.

But the House Republicans, under the shaky leadership of Speaker Kevin McCarthy, R-Calif., occupy a place that the Greek playwright Aristophanes aptly called “Cloud-Cuckoo Land.” Which is why it is possible that Republicans, in their ideological zeal, will both refuse to fund the government by Oct. 1 and impeach the president.

The politics of obstruction can be justified on rare occasions on Capitol Hill.

I came of age revering those members of Congress with the gumption to denounce the folly of the Vietnam War. The same can be said for those legislators who were appalled by former President George W. Bush’s heedless decision to invade Iraq.

In reality, there are just two possible real-world justifications for kamikaze tactics in Congress: Either they will eventually lead to better policy outcomes or else they carry with them political, if not practical, benefits.

But where is the policy upside for the Republicans in a government shutdown?

Right now, it isn’t even clear why the GOP incendiaries are so determined to go to the brink on the budget. Is it over spending levels, border security, support for Ukraine — or general annoyance that the Democrats control the White House and the Senate?

Impeachment makes even less sense unless Republicans’ secret dream is to make Kamala Harris the president of the United States. You don’t need a formal Senate trial to guarantee the ethically sleazy Hunter Biden, son of the sitting president, will never hold high political office.

For nearly six decades, the GOP has been crusading against the permissive excesses of the 1960s. But right now, Republicans like Georgia Rep. Marjorie Taylor Greene are following the 1960s hippie mantra “If it feels good, do it.”

It feels good to shut down the government to drive Biden and the Democrats bonkers. It feels good to start impeachment proceedings so GOP firebrands can shout about “the Biden crime family” and “Hunter Biden’s laptop.”

The political ramifications of these Rumpelstiltskin, stamp-your-feet tactics are even worse. There is one historical constant that comes with major government shutdowns: Republicans are blamed more than Democrats.

House Speaker Newt Gingrich, R-Ga., exercised his power to say no with a 21-day shutdown beginning in mid-December 1995. After federal workers returned to their offices in January 1996, an ABC News-Washington Post poll found 50 percent of Americans blamed Republicans for the disruption and only 27 percent chastised then-President Bill Clinton, a Democrat.

Even more relevant for McCarthy and Co. is the polling from the 16-day government shutdown in 2013, when Republicans foolishly tried to bludgeon then-President Barack Obama into repudiating his signature domestic achievement, the Affordable Care Act.

At the height of the 2013 shutdown, a Pew Research Center Poll found just 19 percent of Americans approved of how Republicans in Congress were “handling negotiations over the government shutdown.”

Polling wasn’t much better for the GOP when Donald Trump provoked a 34-day government shutdown that bridged the end of 2018 and the start of 2019 over his demand that the Democrat-controlled House fund his proposed southern border wall. After the unnecessary crisis was resolved in late January 2019, a Monmouth University Poll revealed that 50 percent of Americans blamed Trump for the crisis while 35 percent held the Democrats responsible.

Rebels without a cause

When it comes to impeaching Biden, House Republicans are rebels without a cause — or, at least, a smoking gun.

Even though no president has ever been convicted after an impeachment trial, the evidence was clear-cut in all modern attempts to remove a president from office.

Richard Nixon, who resigned in 1974 to avoid impeachment and conviction, was unequivocally guilty from the White House tapes of obstruction of justice in covering up the Watergate break-in.

Whatever you think of the merits of the House Republicans impeaching Clinton in late 1998, he did lie about sex under oath and took sexual advantage of a young White House intern.

There was nothing ambiguous about the two Trump impeachments.

The first time around in 2019, Trump tried to shake down Ukrainian President Volodymyr Zelenskyy for dirt on Joe and Hunter Biden in exchange for congressionally funded military aid. The armaments were not just for military parades, as it turned out that Ukraine has real enemies — one of them, Russia, invaded after Trump left office.

And in 2021, there was that business about an insurrection and Trump’s efforts to illegally overturn a valid presidential election.

In contrast, what’s the one-sentence rationale for impeaching Joe Biden?

He was too indulgent with his scapegrace son? Or that Hunter Biden benefited financially from his father being vice president? (If that’s the impeachable offense, then maybe we should discuss Ivanka Trump and her husband, Jared Kushner).

In truth, House Republicans would be impeaching Biden with the rationale: “If we dig deep enough, certainly we have got to find something.”

Think of the 18 House Republicans who represent districts that Biden carried in 2020. McCarthy needs almost all of their votes to hold the line on not funding the government and to impeach Biden.

How would a government shutdown affect their reelection chances? How would voting to impeach the president on nebulous grounds play with their pro-Biden constituencies? Especially if, as is quite plausible, a majority of Senate Republicans find Biden “not guilty.”

More than 85 percent of House Republicans should remember how frustrating life was before 2021 in a minority under Speaker Nancy Pelosi. But these GOP veterans must be nostalgic for those days of ineffectuality since they are doing everything in their power to bring back a Democratic House majority.