Have Democrats Always Been the "Immigrant Party?"

[electionsguy259]

I was reading a post from Noahpinion talking about how native-born Americans have always feared the political influence of newly-arrived immigrant groups, tracing back to the Irish in the 18th-19th centuries. He makes the interesting point that just as most immigrant groups vote Democratic today, the Irish immigrants back then voted for the Jeffersonian Democratic-Republicans (and eventually the Democratic Party after 1828).

Does anyone know whether this is just a coincidence or if it reflects something inherent about the Democrats (and their opponents). And yes, I acknowledge there are a few immigrant groups- such as Cuban-Americans or Vietnamese-Americans- that are exceptions to the rule.