Economist: The wages of many of the lowest-paid corporate employees in this country would be protected from cuts by enacting a maximum wage law that prohibits executives at any corporation from earning more than, say, 50 times what the corporation’s lowest-paid employees in this country earn.
Conclusion
Setting a max wage would protect the country's lowest paid corporate employees from wage cuts.
Evidence
Setting a max wage would remove one incentive (cutting employee pay in order to boost profits and thus executive salaries) for cutting the wages of the lowest paid employees.
Evaluate
The author seems to be assuming a couple things: - if you remove an incentive for doing X, people will no longer do it for that reason - if you remove an incentive for doing X, there isn't some other incentive that would still be a compelling reason to do X
Maybe with a max wage law, executives would no longer have the incentive to cut wages for the sake of increasing their own salaries, but they would still have the incentive to cut wages for the sake of increasing profits so that they could flatter their vanity by appearing on the cover of Forbes for their super-profitable business.
Salary isn't necessarily the only thing motivating wage cuts.
Goal
Look for an answer ruling out some other reason why executives would want to cut wages, or for an answer that just connects the language of premise to conclusion: .