Delaware law, the corporate law that governs most of the 'important' corporations in the U.S., will apply some sort of heightened scrutiny. They'll make managers provide a 'compelling justification' for actions that effectively deprive shareholders of voting rights. After all, an important rationale for courts' 'hands-off' approach to corporate business decisions is that shareholders have elected the people who made those decisions. Corporations are 'supposed' to be run by people who shareholders elect - if shareholders don't like those people, they can vote them out and elect new ones. Federal securities law applies too to the conduct of many types of 'organic change' transactions, as I'm calling them.
Some states have takeover laws.
In sum, the hostile bidder's bid may be made more expensive, but it can't be made impossible. Subsequent statutes have been drafted to withstand such challenges. Note, too, that some states permit corporations to 'opt out' of their anti-takeover statutes. Indeed, some shareholder activism has been directed at getting companies to exempt themselves from these laws where doing so is possible. More than 20 states have such statutes.