(A version of this questionthis question for undirected graphs.)
Let $G=(V,E)$ be a finite, simple, undirected graph. For $v\in V$ set $$ N(v) := \{x\in V: \{x,v\}\in E\}. $$ Is it possible to find a partition $P_1,P_2$ of $V$ such that for every $P_i$ and $v\in P_i$ we have $$|N(v)\cap P_i| \leq |N(v)\cap(V\setminus P_i)|$$?