Forget Sanders and Clinton for a moment. This is a symbolic schism that has been long brewing

[RichVRichV]

286. Now you're confusing the NLRB.

The responsibility of approving mergers falls to the FTC and DoJ. They enforce the anti trust acts. They can deny any merger that threatens market control or creates a monopoly in an area. In fact it was much more difficult for large companies to get approval before the 80's. The government doesn't need to sue anyone to prevent large mergers.

We do have many monopolies in this country. Most power companies, cable companies, and phone companies are legal monopolies. It's why they have to get regulatory approval for rate hikes. Also most professional sports are monopolies and have to have regulatory exemption to collude. Plus we have many industries that are dominately controlled by only a few companies that used to be hundreds or even thousands of smaller companies.

Oh and the "efficiency" touted by larger corporations is usually achieved by laying people off from redundant positions, if not outright shipping those jobs oversees to cheaper markets. Small businesses weren't the ones moving production over to China.