We propose a novel technique that maps decision problems in WS1S (weak monadic second-order logic with n successors) to the problem of query evaluation of Complex-value Datalog queries. We then show how the use of advanced implementation techniques for Logic Programs, in particular the use of tabling in the XSB system, yields a considerable improvement in performance over more traditional approaches. We also explore various optimizations of the proposed technique based on variants of tabling and goal reordering. Although our primary focus is on WS1S, it is straightforward to adapt our approach for other logics with existing automata-theoretic decision procedures, for example WS2S.