"The Interstate Commerce Act of 1887, establishing the Interstate Commerce Commission (ICC) had been an early effort to regulate the industry; but over the years, the courts had sharply limited its influence." - wiki

Would the Interstate Commerce Act of 1887 be considered a policy for the "Square Deal" even though it wasn't Roosevelt who passed it?

I would think yes since it's a course of action taken.

but I'm not sure if the Act was a key policy for the "Square Deal".

Yes, it was. See the Hepburn Act.

http://www.presidentprofiles.com/Grant-Eisenhower/Theodore-Roosevelt-The-ripening-of-the-square-deal.html

And, you can search on Hepburn Act. Before that, the ICC was very restricted on actual control of commerce.

So, the policies would be the Interstate Commerce Act of 1887, the Interstate Commerce Commission, Hepburn Act, Sherman Antitrust Act ... and more

yes.

Yes, you are correct in thinking that the Interstate Commerce Act of 1887 could be considered a policy aligned with the principles of the "Square Deal," even though it was not passed by President Roosevelt. The Square Deal was a set of progressive reforms advocated by President Theodore Roosevelt during his presidency (1901-1909). It aimed to address social and economic issues by promoting fairness and protecting the rights of the average citizen.

The Interstate Commerce Act of 1887 played a significant role in regulating the transportation industry and was one of the earliest attempts by the federal government to address issues of fairness and prevent discrimination in the railroads. It established the Interstate Commerce Commission (ICC), which was tasked with enforcing regulations to ensure fair practices in the railroad and transportation sector.

Although the Act was passed years before Roosevelt's presidency, it aligned with the principles of the Square Deal by promoting fairness and regulation in the industry. Roosevelt, during his time in office, continued to push for similar progressive policies and supported the enforcement of regulations to protect consumers and workers.

In summary, while the Interstate Commerce Act of 1887 was not directly passed by Roosevelt, it can be viewed as a precedent for the type of policies he advocated under the Square Deal.