Complex sentence: In 1965, however, the Justice Party of Süleyman Demirel won an absolute majority, which it increased in 1969, but there was increasing polarization between the Justice Party on the right and the Republican People's Party of İsmet İnönü and Bülent Ecevit on the left.
Split into simpler sentences: In 1965, however, the Justice Party of Süleyman Demirel won an absolute majority, which it increased in 1969. But there was increasing polarization between the Justice Party on the right and the Republican People's Party of İsmet İnönü and Bülent Ecevit on the left.