AP was born as an anti-establishment party in 1993 , in parallel with the rise of Lega Nord in Italy , of which it has been long considered the Sanmarinese counterpart , but has since then become a stable political force in San Marino , participating in government coalitions with the centrist Sammarinese Christian Democratic Party ( PDCS ) as well as with the centre-left Party of Socialists and Democrats ( PSD ) since 2002 .