The law did not recognize sex-based discrimination in 1908; it was unrecognized until the case of Reed v. Reed in 1971; here, the test was not under the equal protections clause, but a test based on the general police powers of the state to protect the welfare of women when it infringed on her fundamental right to negotiate contracts; inequality was not a deciding factor because the sexes were inherently different in their particular conditions and had completely different functions;[2] usage of labor laws that were made to nurture women's welfare and for the "benefit of all" people[3] was decided to be not a violation of the Constitution's Contract Clause.

"[3] "her physical structure and a proper discharge of her maternal functions — having in view not merely her own health, but the well-being of the race — justify legislation to protect her from the greed as well as the passion of man.

[7] Curt Muller, the owner of a laundry business, was convicted of violating Oregon labor laws by making a female employee work more than ten hours in a single day.

[9] Groups like the National Consumer League (which included Florence Kelley and Josephine Goldmark as feminists) and the state won shorter hours for women.

However, many equal-rights feminists opposed the ruling, since it allowed laws based on stereotyped gender roles that restricted women's rights and financial independence.

The government interest in public welfare outweighed the freedom of contract that is displayed in the 14th Amendment and the effects of Muller v. Oregon did not change until the New Deal days in the 1930s.

Kessler-Harris recognized the admirable motives of the period's protective labor laws but also observed that the Muller case provided justification for not just regulating but possibly prohibiting women from working in certain capacities.

"[14] "Until the late 1930s, when the Fair Labor Standards Act created gender-neutral workplace protections, the Equal Rights Amendment championed by the NWP would have demolished the gains for women workers won in Muller.