Why was it so difficult to resolve such issues as the spoils system, the tariff, and bimetallism, which consumed congressional energies in the late nineteenth century ?

Corruption

Explanation:

it is so difficult to find solutions to such issues as the spoils system, the tariff, and bimetallism, which drained congressional energies in the late nineteenth century because of corruption. The United States government was very corrupt during the said period.

In the nineteenth century, most government officials were only after their personal gain and doesn't have the interest of the nation and the citizens at heart. During the time many corrupted government officials made lot of money or acquired power from the spoit system, the tariff, and bimetallism, This act made it extremely difficult to make free of corrupt ideas from the system.