Later on he attempted to influence the Prussian Northern Union in the direction of the national policy, and he took part in the sessions of the Erfurt parliament; but, soon realizing the hopelessness of any good results from the vacillating policy of Prussia, he retired from the contest, and, as a major in the service of the SchleswigHolstein government, took part in the Danish War of 1850.
Throughout the revolutionary years he supported his brother's policy, became a member of the Erfurt parliament, and, after the collapse of the national movement, returned to the service of the duchy of Nassau.
In 1848 he was elected to the lower legislative chamber of Baden, and in 1850 advocated the project of union with Prussia at the parliament held at Erfurt.
Such were the discouraging conditions which weighed him down at the time of the interview with the tsar at Erfurt (September 27th - October 12th, 1808).
Apart from this advantage, placed in his hands by the imprudence of Stein, Napoleon was heavily handicapped at the Erfurt interview.