Bernie Sanders speaks at a campaign event in Amherst, Mass., January 2016. (Mary Schwalm/Reuters)

Bernie Sanders (I., Vt.) has introduced legislation to tax companies for the federal benefits their employees receive, unsubtly called the Stop Bad Employers by Zeroing Out Subsidies, or BEZOS Act. Leave aside for now the ominous nature of naming a piece of federal legislation after an individual, solely due to legislative animus at that individual’s financial success. Let’s look at how this would operate in practice:

The bill would establish a 100% tax on companies equal to the benefits their employees are receiving. Covered public assistance program include Medicaid, Section 8 housing, the Supplemental Nutrition Assistance Program and the National School Lunch and School Breakfast programs, for companies with more than 500 employees.

You may, reading this, be picturing the avenging angels of the federal government — dispassionate, omniscient, charged by President Trump with sharing his high integrity and commitment to the even-handed and sober-minded enforcement of all the laws — sweeping in every April 15 to hand down the tax bill for this on graven tablets. But that is not how corporate taxation works.

The reality is that any plausible system of enforcement under legislation of this nature would in practice require big companies to ask a huge, new number of invasive questions of their employees in order to determine who is in their family or household and what federal benefits such people receive. And, by imposing costs on the company proportional to such benefits, it will strongly incentivize companies to find ways to avoid employing, say, single mothers who receive a lot of benefits. Preventing such discrimination, when the government is clobbering businesses over the head with economic reasons to engage in it, will require even further commitments of resources (And you know who doesn’t get federal welfare benefits? Offshore workers, and robots). To say nothing of the fact that audits of companies that employ a lot of people suspiciously not applying for federal welfare benefits would swiftly reveal companies that employ a lot of illegal immigrants (if you’re a liberal, just be thankful that nobody running the executive branch these days would think to do that). Any system of enforcement that tried to bypass the employer as information-gatherer would inevitably look like the e-verify system desired by immigration hawks.

As always, when you set the wheels of big government in motion, be careful what you wish for. You might get it, good and hard.