Hamilton was himself an immigrant but was surprisingly against Thomas Jefferson's open immigration policies. Hamilton was concerned about french influence on american politics. Even after the french revolution, Jefferson and his democratic-republican party stayed attached to the french. Hamilton said "the safety of a republic depends essentially on teh energy of a common national sentiment." Hamilton also believed that immigrants will be apt on bringing a part of what they left behind and wouldn't fully separate with their nationalism for their home country.
https://amgreatness.com/2016/12/21/hamiltons-actual-views-immigration/
