In the autumn of 1903, Shtif cofounded the Vozrozhdenie (Renaissance) Jewish socialist group in Kiev with A. Ben-Adir and W. Fabrikant. Shortly thereafter, he was arrested for his political activities and was expelled from the Kiev Polytechnic University. From late 1904 until early 1906, he lived in Bern, Switzerland, where he organized a local Vozrozhdenie group and agitated against the General Jewish Labour Bund in Lithuania, Poland and Russia. In April 1906, with other activists from Vozrozhdenie, he founded the Jewish Socialist Labor Party in Kiev. Its members, also known as Sejmists, sought Jewish national autonomy in Russia and became committed Yiddishists.