In what way did loyalty to the United States factor into anti-catholic sentiment during the 1800s?

Back then, the anti-Catholics believed that Catholicism was not compatible with democracy.

They believe that Catholicism kept the people who followed it from becoming loyal Americans

Some Americans saw an allegiance to the Roman Catholic Pope as an allegiance to a foreign political leader, which meant the loyalty of Catholics could never lie with americna leaders. These non-Catholics believed a lack of loyalty to US political ideas and leaders by Catholics would undermine the democratic system.