“A republic, if you can keep it,” Ben Franklin famously described the new Constitution in 1787. Well, can the Republicans keep it, or will they let it slide into authoritarianism? I, like Franklin, am an optimist, but GOP senators will have to make prompt choices on Trump’s frantic Supreme Court nomination.

It is now clear why President Trump insists on filling Ruth Bader Ginsburg’s seat with Federal Appeals Court Judge Amy Coney Barrett — so conservative she’s radical — before the November election. If the initial election count goes against him, Trump will call it fraudulent — due to mail-in ballots — and unfold a plan whereby Republican-dominated state legislatures certify an alternate list of Trump electors for the Electoral College. (This from The Atlantic’s scary new piece by Barton Gellman.)

If that is challenged in a stacked Supreme Court, “originalist” Republican justices could find it constitutional, 6-3. The Constitution does give that power to state legislatures. But with the “original intent” that state legislatures faithfully reflect the majority vote. Federalists find original intent where it suits them.

Likewise, as Trump’s financial shenanigans — exposed in tax and bank records — come to light in New York state trials, Trump’s defense will insist on moving them to federal courts and then bumping them up to the Supreme Court. Which will find that Trump cannot be prosecuted. Trump could thus become not only illegitimate but invulnerable. Net winner: Putin.

The fateful question: Will sufficient Senate Republicans sense how dangerous this is and vote either against speedy consideration or against confirmation? If just four Republicans say “no,” Mitch McConnell would have only 49 votes, not enough for Vice President Pence to break a tie.

As events rapidly unfold, some Republicans are developing qualms. Will Maine’s Senator Susan Collins? She claims to be independent in the mold of Margaret Chase Smith. Now she can prove it. Which will matter more, White House pressure or voter wishes? I think she’ll side with voters. Incumbent Republican Senators in tough contests may discover they aren’t so close to Trump after all.

Barrett’s confirmation would make a Supreme Court of seven Catholics and two Jews. (One Catholic, Justice Sonia Sotomayor, however, is a liberal.) Pretty funny. For most of its history, the Supreme Court has been a club of white, male Protestants. For the sake of diversity, I propose reserving at least one seat for a Protestant.

The Court itself may block the authoritarian drift. The five present conservative justices are all current or previous members of the “originalist” Federalist Society, as is Barrett. They may favor the Constitution over Trump. If there are nine on the court (assuming Barrett is confirmed), two conservatives may be unwilling to pervert the Constitution, producing a 5-4 decision against Trump. If there are only eight on the court, one defection would tie it 4-4 and let the lower court’s decision stand. Best bet: Chief Justice Roberts.

But all these barriers to authoritarianism could fail. Does this mean the end of the United States as we know it? The Democratic majority of voters and at least one house of Congress may be able to thwart Trump’s worst designs, but planning should start now.

COVID-19 deaths will approach a quarter-million by election day. “Herd immunity” (about 70 percent carrying antibodies) and vaccines will not arrive for months or even years. With the scientific staffs of federal health agencies silenced by unqualified political appointees, we must learn to work around their misinformation. A nongovernmental committee of scientists should serve as a data clearinghouse and alert system. To some extent, this is already happening.

At least one house of Congress — it could be both in 2021 — could deny Trump the laws and budgets he demands. Ripe targets: Trump’s Mexico wall and unnecessary military spending. Step up cyber defense spending and require intel agencies to promptly report efforts at penetration. Pass more unemployment relief than Trump wants; make him veto it. Ally with anti-deficit Republicans to crimp Trump’s spending patterns.

Barrett scorns precedent and hates the Affordable Care Act. If it’s overturned, closely scrutinize Trump’s replacement for it. He has never produced one, but he may have to. It will contain cavernous faults, especially on pre-existing conditions. Find Trumpcare defective and sink it. When Trump supporters lose their rural hospitals, some may change their vote.

In foreign policy, send congressional delegations to the multilateral meetings and institutions Trump rejects. These include global climate change, the Iran nuclear deal and trade flows (e.g., the Trans Pacific Partnership). Work around the hobbled State Department. (Many State officials will quietly help you.) If Trump leads us into war with Iran, reject authorization for the use of military force and restoring the draft.

So, even if worse comes to worst, we may survive. Out of the wreckage, traditional Republicans will reconstruct and join Democrats in restoring a badly weakened Republic. Yes, I think we can keep it.