Over the weekend, Becker and Posner took their respective shots at the UAW … and unions, in general.

I believe great value can be offered by unions of freelancers — e.g., common artisans whose pay is primarily derived from diverse but finite projects rather than from single-entity employers — but I tend to share Posner’s and Becker’s doubts about the role and value of other unions; namely, those that organize workers at companies that would probably (or already do) offer competitive wages and benefits, even in a non-union environment.

In short: Like Becker and Posner, I’m not an avid supporter of the UAW and its ilk. I am, however, an avid supporter of fair play, namely: If the major U.S. automakers seek union wage concessions, they should be willing to match or beat those concessions with executive-compensation adjustments.

To illustrate:

Posner writes, “The total wage and benefit bill [excluding retirement benefits] for the Detroit automakers is about $55 per hour, compared to $45 for workers in the foreign-owned plants.” That appears to be consistent with FactCheck.org’s apples-to-apples estimate.

Asking the UAW to agree to a reduction of the hourly wage-and-benefit rate from $55 to $45 represents a cut of approximately 18%. In turn, if Detroit automakers ask union workers for an 18% cut, they should (at the very least) pledge a comparable cut in executive compensation. Let’s call it 20% for the purposes of this exercise.

Next, consider the core compensation (salary plus non-equity incentive plan comp) for the five top GM executives listed at this source. According to that source, those five executives collectively received core compensation of approximately $10.7 million in 2007. Adjusted downward by 20%, they would be collectively paid $8.6 million instead — saving the company around $2.1 million annually, while still allowing those five execs to earn an average of $1.7 million each in 12 months.

Granted, you could argue that it’s less onerous for an executive making $2.1 million per year to take a $400,000 pay cut than it is for a factory worker earning $60,000 per year to take a $12,000 pay cut — and thus, executive cuts should be greater than 20 percent, perhaps 30 or even 40 percent. (At a 40 percent cut, the five listed execs would make an average of $1.3 million per year.)

But even at a “mere” 20 percent cut for the execs, I think the workers would be a lot more willing to bargain, and the court of public opinion a lot more forgiving than it’s inclined to be right now.

Of course, if the Big 3 execs have already offered such cuts to their own compensation, or are planning to, I commend them. If not, I suspect they’ll quickly lose the PR battle in their efforts to negotiate UAW concessions. And once again, I say that as a non-fan of the latter.