Donald Trump has a reasonably good chance at winning a second presidential term. So anyone who wants to influence what he does in office had better move fast.

One option for Republican donors who are not big Trump fans is to stay on the sidelines in the presidential race and concentrate resources on the effort to win Republican control of the Senate. If Trump winds up winning, the thinking goes, one can always buy in afterward with a contribution toward the inaugural festivities, say, or by helping to retire any campaign debt that Trump accumulates.

Yet Trump, with all his divorces and vaunted “Apprentice”-style “firings,” also values long standing relationships. It may be too late in the campaign for the Democratic “Emily’s list” adage that “early money is like yeast.” It’s not too late for potential donors and volunteers to qualify for Trump’s treatment by the terms of another political saying, “dance with the one that brung you.” 

A professor at Antonin Scalia Law School, David E. Bernstein, flagged this in a September 12 post on social media. “If you are a sane Republican with qualms about Trump, I’m begging you to join his campaign if you haven’t already, and get yourself in line for a position in the administration,” Mr. Bernstein wrote.

“Regardless of what you do, he has about a 50% chance of winning, and we need people like you in a Trump administration, having it staffed by some combination of the Tulsi Gabbards, Laua Loomers, Tucker Carlsons and RFK Jrs of the world would be an unmitigated disaster.”

To those who argue that Trump is such a loose cannon that he isn’t susceptible to moderating influences, Mr. Bernstein says that the track record of the first term showed otherwise. “The sane people played a huge role in mitigating Trump’s worse instincts,” he wrote. “If you would happily serve in a DeSantis administration, you should bite the bullet and serve in Trump II.” 

The first Trump cabinet included several people — Steven Mnuchin at Treasury, Wilbur Ross, at Commerce, Betsy DeVos at the Department of Education — who came from the business world or had backgrounds as wealthy donor-activists. Sheldon Adelson did not join the administration but achieved some of his policy goals, including a move of the American embassy in Israel to Jerusalem and an end to the Iran nuclear deal. 

The Democrats have their own equivalents: the New York Times recently highlighted the friendship between Laurene Powell Jobs and Kamala Harris. Alex Soros was posting about Governor Walz’s visit to Soros’s Manhattan apartment, with its high ceilings and skyline views. President Biden made sure to stop this week at Michael Bloomberg’s Global Business Forum.

Critics of Trump find him transactional. That can be construed as honest, though. The pattern is that he does what he says he’s going to do. There’s less of a worry with Trump that he takes your money and then freelances his own policy. That is more of a risk with many other politicians. Once you buy Trump, he stays bought, which is its own rare kind of integrity in a politician.

I don’t mean to be cynical or crass about it or suggest Trump has done anything illegal or inappropriate. I do mean to suggest that if you want something from Trump in term two, prices are only going up after Election Day, and inventory is going fast. The cryptocurrency people have already been through. 

What are some examples of policies where there is enough uncertainty that a savvy political player might be able to have a voice? How much “mass deportation” there will be is one policy question sure to be a hot issue early in the administration. Another would be whether Trump’s tariffs will actually be revenue-generating or mostly a negotiating bluff for reciprocity to get other countries to lower their trade barriers.

How much Trump proposes to raise defense spending, the contours of any attempted new Trump deal with Iran, how much Trump invests in nuclear power, what a Trump-Care replacement for Obamacare looks like, whether any Ukraine independent of Russia survives, whether Trump pardons Hunter Biden in a magnanimous gesture against lawfare — all this is potentially up for grabs.

Many of these debates may fester unresolved well into a second Trump administration, if there is one. To use a market metaphor, though, shares in the initial public offering in a second Trump administration are available for allocation. If you sign up now, you might, depending on what happens on Election Day, benefit from an opening day pop.