These are divisive times. But Americans should be able to agree on at least one issue: Sen. Marco Rubio (R-Fla.) shouldn't be the arbiter of what political expression is or isn't allowed in America.

Rubio is leading the effort to pass the "Combating BDS Act," a law that would give the federal imprimatur to state and local governments that pass laws against giving government contracts to individuals and companies that boycott the State of Israel in opposition to its policies regarding the Palestinian territories.

That act — part of a larger package of measures regarding Middle East policy — suffered a setback this week, thanks to a Democratic filibuster. But Rubio and the anti-boycott movement aren't done.

"Opposition to our bill isn't about free speech," Rubio tweeted Tuesday. "Companies are FREE to boycott Israel. But local & state governments should be FREE to end contracts with companies that do."

A good rule in politics: If you have to say a proposed law isn't about free speech, it's probably about free speech.

The courts, at least, seem to disagree with Rubio. Federal courts have blocked anti-BDS laws in Arizona and Kansas, the latter of which required any individuals and companies that contract with the state to certify they are "not currently engaged in a boycott of Israel." Those rulings followed a long legal history: The Supreme Court ruled in the 1990s that local governments can't fire contractors for protected political speech.

That's a good thing. Boycotts, after all, are a long-established political tool, both in the United States and abroad. Perhaps most famously, Martin Luther King Jr. led a boycott in Montgomery, Alabama to protest the racist policies of the bus service in that city after Rosa Parks refused to give her seat to a white passenger. In just the last few years, conservatives have boycotted Nike — even burning their shoes in protest — in response to an ad that featured Colin Kaepernick, the quarterback known for his protest against police brutality, while liberals have mounted boycott campaigns against companies that do business with the NRA or advertise on Fox News shows. There are even boycotts against Chik-fil-A.

Why should Israel be off limits?

The country, after all, has thrived in its modern incarnation for more than 70 years located in a pretty hostile Middle Eastern neighborhood. It has nuclear arms and is the recipient of billions of dollars in U.S. military aid. It seems resilient enough to survive a decision by a few Americans to spend their dollars elsewhere.

You don't have to weigh the merits of Israeli policy, though, to think Rubio's bill is bad. The ACLU, for example, is fighting against anti-BDS laws but hasn't taken a position for or against these boycotts themselves. The argument isn't about whether such boycotts are good, wise, or just. It's about whether state, local, and federal governments in the United States should be able to punish people — like an attorney who provides legal services for poor defendants, or a teacher who helps other teachers get ready for the classroom — for making the political decision to boycott something.

"Public officials cannot use the power of public office to punish views they don't agree with," the ACLU said in a blog post. "That's the kind of authoritarian power our Constitution is meant to protect against."

That's exactly right. Certainly, Rubio isn't against boycotts per se: The bill, he explained in a tweet this week, "allows local & state govt's to boycott the boycotters by ending contracts with companies that give in to these Anti-Israel demands." He wants to punish Americans not for doing the wrong thing, but for thinking the wrong thoughts.

At some point, the ongoing government shutdown will end. It's possible that opposition to Rubio's anti-boycott bill will subside as a result — Democrats filibustered the bill this week in part because they were blocking any Senate action until the standoff is over. But I would argue the controversy over the boycott movement is likely to get louder: The Birmingham Civil Rights Institute just rescinded an award to lefty icon Angela Davis because she supports boycotting Israel.

In coming months, then, it seems likely the movement will spark discussions and arguments among neighbors, in churches, and across any number of American communities. It's up to individuals to decide how and if they'll act — Rubio and the U.S. government shouldn't get to decide for them in advance.