Which part of the Compromise of 1850 created the most controversy during the
1850s?

The fugitive slave act.

Explanation:

Of all the bills that made up the Compromise of 1850, the Fugitive Slave Act was the most controversial. It required citizens to assist in the recovery of fugitive slaves. It denied a fugitive's right to a jury trial.

the respondent is the party against whom a petition is filed