In 1848, revolution spread across the European continent. While initially having great success, the revolution had died within a year or so.

The 1848 revolution seems unique in that the veterans of the losing side seemed to have mostly escaped death and imprisonment. Many would eventually emigrate to the US. What happened that made this possible?

My interest in this comes from family ancestry research. My great-great-great grandfather supposedly fought in both the 1848 revolution and the American Civil War. I had been suspicious of this claim but recently found a number of historical figures who had similar stories like Franz Sigel and Carl Schurz.

Another question more towards the Civil War angle, were native Americans concerned at all that these German immigrants would try to bring their revolutionary ideas to the US? Did they face extra scrutiny in the immigration process?