What was the primary goal of the populist party

The Populist Party was a short-lived political party in the late 19th century United States (1891-1908) and was officially called People's Party. It was particularly popular with farmers in the western US, largely due to their opposition to the gold standard. Although the party did not remain a permanent feature of the political landscape, many of its positions were adopted by others over the following decades. The term "populist" has since become a generic term in US politics and describes a policy that is directed against the establishment interests, in favor of the common people.

the constitution gives congress the power to regulate commerce "among" the several states.

it required the unanimous approval of the states before the congress could enact any measure.