In 1930, Lubomirski resigned from the Senate in protest against the Brest trials, but Prime Minister Walery Slawek did not accept the resignation. Lubomirski disliked the so-called colonels’ regime, and in the late 1930s, he organized several secret meetings, in which political situation of the Second Polish Republic was discussed. The sanacja government was aware of it, and blocked Lubomirski's run for Senate election in 1938. Meanwhile, Lubomirski continued his charity activities, as member of several civic organizations.