The next chapter of CBS Corp.'s ongoing feud with Shari Redstone is set to turn on the validity of a board of directors' vote late Thursday to strip its controlling stockholder of her voting power and whether Redstone's National Amusements Inc. has the authority to block the move.

While a leading observer expects Redstone to make the next move, it was uncertain at the end of a dramatic week whether she or the CBS board would act first in their battle for control of the company, and over a potential merger of CBS into Viacom Inc.

The outcome of the case will ultimately be left to the Delaware Court of Chancery to decide; however, it was not clear on Friday how the dispute would play out, after a whirlwind week of maneuvering that ended in a stunning rebuke of Redstone and her sway over the media giant.

CBS said Thursday evening that 11 out of the company's 14 directors had authorized a stock dividend to dilute Redstone's voting control from nearly 80 percent to about 20 percent, amid fears that she may try to force a merger with CBS' sister media company, Viacom. The dividend, CBS said, would not take effect until the court rules that it is permissible.

National Amusements, meanwhile, argues that the dividend was altogether invalid, after it amended the CBS bylaws earlier in the week to require 90 percent of CBS' directors to approve board actions that would threaten its president's voting control power.

According to National Amusements, the bylaw changes went into effect immediately after they were enacted on Wednesday, less than an hour before a hearing in front of Chancery Court Chancellor Andre G. Bouchard in Wilmington. Redstone and National Amusements believe a ruling from Bouchard Thursday morning means that CBS would need to lodge a court challenge of the supermajority requirement in order for it to be found invalid—and not the other way around.

CBS has already committed to challenging the amendments to its bylaws. The company maintains that the changes are not allowed and would take 20 business days to go into effect, anyway.

Neither CBS nor National Amusements would comment Friday on the current landscape of the dispute or which side would act next in Chancery Court.

Charles M. Elson, a professor of corporate governance at the University of Delaware, said he expected Redstone to make the next move in light of a vote that purported to eliminate her voting power.

“She'll sue to reinstate her voting rights,” he said. “My suspicion is she certainly will argue her dilution is improper.”

However, in contrast to the breakneck speed of the past week, the case is expected to take months to litigate.

The fight centers on CBS' contention that Redstone is trying to force a merger with Viacom, which split from CBS in 2005 under the tenure of Redstone's ailing father, Sumner Redstone, who had served as executive chairman of both CBS and Viacom. National Amusements, the Redstone family's holding company, has since maintained a controlling stake in both companies.

CBS and a committee of five independent directors filed a lawsuit Monday morning accusing Redstone of breaching her fiduciary duties and seeking a temporary restraining order to prevent her from making any changes to the CBS board ahead of Thursday's dividend vote.

National Amusements has said she does not want to oust CBS directors, and the company has repeatedly denied any intention of ”forcing a merger that is not supported by both CBS and Viacom.”

On Thursday, Bouchard said CBS had made a “colorable claim” for breaches of fiduciary duties by Redstone and National Amusements, but he ruled that CBS would not suffer irreparable harm without a restraining order.

“To the contrary, the court has extensive power to provide redress if Ms. Redstone takes action(s) inconsistent with the fiduciary obligations owed by a controlling stockholder,” Bouchard said.

Delaware corporate law allows a company or its shareholders to challenge the removal of directors, and the Court of Chancery to address any merger that is the product of fiduciary breaches.

“To be sure, litigation over these types of issues takes time, is expensive, and can be distracting and messy. But that does not mean that full relief would not be available if the present motion is denied,” Bouchard said.