Last fall, Gov. Murphy signed legislation allowing Cory Booker to run for senator and president simultaneously. Sure, the new law doesn’t specifically mention Booker, but no one else is in the position to do so.

This didn’t get all that much attention at the time, coming as it did less than a week before the midterm election.

But now Sen. Booker is officially running for president and the impact of the law has become a bit clearer – at least to those asked about it in a recent Monmouth University poll.

And guess what? Most people don’t like the arrangement.

The poll put it this way:

“One thing New Jerseyans of all political stripes agree on is that Booker should forego seeking reelection to his current office if he happens to win his party’s presidential nomination.”  In fact, just 21 percent of respondents said he should run for both offices at the same time. This sentiment crosses party lines.

Keep in mind that the law also would cover any Booker run for vice president.

It is true that what happened in New Jersey is not unique. Many such laws have been passed over the years by other states.

Still, as many ordinary people see, this is one of those laws politicians pass to benefit not the public, but each other.

The public also remembers not too long ago how then Governor Chris Christie spent considerable time away from Trenton, first as head of the Republican Governors’ Association and then as a presidential candidate.

Running for president really can be a full-time job. Being one of 100 senators does not usually carry the executive responsibilities of a governor, but it is, of course, a significant position. There are, as we just said, only 100 of these people.

When Christie was confronted by this issue. he contended that times are very different today, and that modern communication allows one to “stay in touch” with New Jersey no matter where you are.

That’s certainly true, but there’s more to the issue.

Just what job do you really want?

Clearly, Booker wants to be president. But like many office-holders, he’s reluctant to give up his “day job.” It’s easy to see why. This is a Democratic state and Booker is a charismatic Democrat. Talk about a safe Senate seat.

The problem is – communication of the day aside – it can be difficult to run and serve at the same time.

The poll said that only 34 percent of respondents said Booker will be able to serve effectively as a senator if he is on the presidential campaign trail. Some 58 percent say he will not be.

None of this is surprising. Voters are rightly cynical about someone running for two offices at the same time. Of course, it’s hard to see Booker suddenly giving up his seat or announcing he will not run again for the Senate.

Asked about precisely that during a meeting with reporters outside his Newark home two weeks ago, Booker said his goal is to become president. Of course.

Looking ahead, Booker probably will continue to lay the groundwork for his presidential run. He already has visited early-voting states in next year’s Democratic primary, Iowa and South Carolina. And he plans a swing through New Hampshire this weekend.

If his campaign fails to gain traction, he’ll be out of the race long before the next Senate election in the fall of 2020.

But suppose Booker does get the nomination, or is picked for vice president? If that happens, you have to think a lot of New Jersey voters are not going to like the fact he is running for two federal offices at the same time.

Nor should they.