Going back to the Scots-Irish immigration of over 200 years ago, most immigrants have supported the Democratic Party, as it was the party of the small farmer and the urban worker, vs. the Federalist/Whig/Republican support by the professional and middle classes and the industrialists and merchants. The Scots-Irish immigrants and their children, widespread on the frontier, elected Jefferson and Jackson to the White House. Most later immigrants followed this path. The exceptions to this rule have been few: British settlers in the Northern states after 1840, German and Dutch Protestants, and post-Castro Cubans.
The fact is that increased numbers of Hispanics in the voting booths will cause politics in Nevada, Colorado, Arizona, New Mexico, and eventually Texas and Florida to shift leftward. Combine increasing Hispanic numbers in the Southeast with Yankees migrating from New York and New Jersey into Virginia and the Carolinas and those states are no longer reliably conservative or Republican and become "purple" at best.