I used data from the General Social Survey to analyze the party affiliation and voting habits of immigrants by ethnicity and generation. Importantly, this data indicates that White and non-White immigrants tend to favor the Democrat party more than the general US population does, though Whites do so to a less extreme degree.
The GSS offers a party ID scale that includes the following options: strong Republican, not strong republican, independent near republican, independent, independent near Democrat, not strong democrat, strong democrat, and other. For readability, I collapsed the three Republican and democrat options together.
All the data looked at was collected in the year 2000 or later. Natives were defined as people who were born in the US and who had two parents born in the US, while 2nd generation immigrants were defined as people born in the US who had two parents not born in the US.
Among the general public (take from the same years), 44.1% of respondents were Democrats and 34.5% were Republican, meaning there was a 9.6 point lean in favor of Democrats. Compared to the general population, immigrants of all racial/ethnic groups lean democrat.
It is also interesting to note that, among both Hispanics and Whites, the bias in favor of Democrats is stronger among 2nd Generation immigrants than 1st Generation ones.
The only native group to favor Republicans is Whites. However, this turns out to only be true of Whites when at least 2 of their grandparents were born in the United States.
Even when looking at 3rd+ generation White Americans, there is a slight preference for Democrats among those who have 3 or more grandparents who were born outside of the United States.
It is worth checking how these party ID numbers relate to actual voting. As can be seen below, 2nd generation Whites typically vote in favor of Democrats by a large margin:
Sometimes, it is claimed that immigration should be limited to Whites in order to avoid the Democrats getting an unfair electoral bump from immigration. This data implies that this argument is misleading because even White immigrants favor the Democrat party.