There were several waves of Jewish immigration, although there have been Jews in America since the very first (possibly a few secret Jews even sailed with Columbus, if you can believe that and a few settled New Mexico). German Jewish immigrants tended to be wealthier and better-educated on average. Also, they assimilated much better, as they came in a smaller group and were able to assimilate well, while maintaining their own identity. Quite a few German and French Jews settled in the South, where they got along quite well. They also settled in the more (at that time) settled parts of the mid-west.
In fact, the first 3 Jewish senators were from the South, if I recall correctly.
Yes, the German Jews did assimilate easier, and were much more conservative. I remember in college when I was a poll worker in a GOP precinct worker in Chicago (in 1970), a well dressed German Jew lady of about 85, telling me about the glory days of Republican rule of some mayor of Chicago in the 1920's named Thompson (as a sidebar, the guy who said that if the King of the UK ever came to Chicago, he would hang him), and about the importance of property rights. LOL. But in Cincinnati, their considerable numbers were never cut by the Ashkenazim, and they become part of the GOP establishment.
Judah P. Benjamin was a Jew who was twice elected to the US Senate by LA voters in the decade prior to the civil war. He resigned from that office in 1861 and was appointed to 3 separate positions in Jefferson Davis' cabinet.
He was first appointed to the position of Attorney General where Davis called him ""a master of law and the most accomplished statesman I have ever known." Later he was chosen to be Davis' Secretary of War, then later he became Secretary of State for the CSA. After the fall of the CSA government Benjamin escaped to the Bahamas and then went on to England where he became a prominent, and very wealthy, lawyer.
More about Benjamin HERE