Following the 1960 military coup, Bölükbașı participated at the Constitutional Assembly in 1961 representing the CKMP. However, he rejected in an uncompromising manner to join the coalition government after the 1961 general elections. Bölükbaşı left the CKMP along with 28 other deputies in June 1962, and re-established the National Party (MP) upon his party's joining the 2nd coalition government of İsmet İnönü. He was named leader of the new party. In 1965, his party took part in the coalition government of Suat Hayri Ürgüplü. Bölükbaşı did not take office in the cabinet, and also openly criticized the government. In February 1969, the general assembly of his former party CKMP approved the renaming of the party to today's Nationalist Movement Party (MHP).