He is most notable for securing victory of the Unionist Party through changing the election law and terrorising those who were able to vote.

[citation needed] Rauch was a member of the unionist party that advocated an integration of Croatia and Kingdom of Hungary.

After the Revolutions of 1848, Croatia became a Habsburg crown territory separate from Hungary, but when the Austrian-Hungarian Ausgleich was signed, Austria-Hungary was created and Rauch was appointed as the acting ban (or viceroy) of Croatia on 27 June 1867.

During this time a new Croatian–Hungarian Settlement was negotiated and put in effect by which Croatia reinstated some of its earlier autonomy, but also lost some other rights.

Rauch was made the official ban on 8 December 1868 and remained in office until 26 January 1871.