Grassi also oversaw Georgetown during the British burning of Washington in the War of 1812. He maintained good relations with the American political leaders and with the Russian ambassador to the United States, Andrey Yakovlevich Dashkov, who frequently visited the college. Though he opposed what he viewed as unbridled freedom in the United States, he approved that it was conducive to the free exercise of religion, which was banned by some of Europe's civil governments. He criticized slavery in the United States as being inconsistent with a national spirit of liberty, and considered it the country's greatest flaw, but wrote that the material conditions of some slaves were superior to those of Europe's peasantry, and regarded immediate, universal emancipation as too dangerous. He also wrote of how Black people were children of God and spoke positively of their faith. While he opposed slavery in the abstract, Grassi's appointment as superior of the Maryland Jesuits thrust him into a world in which slavery was accepted and quotidian. As superior, he was responsible for managing the slaves owned by the Maryland Jesuits.