Further, if the full complement of DPJ Diet men who voted no were to leave the party, Noda would thereby lose a majority in parliament, exposing him to the very high risk that his main enter-party rival, Tanigaki Sadakazu, leader of the LDP, will force a vote of confidence in the (now) minority cabinet, in order to force a new general election, from which the LDP might hope to regain power.
FORBES: For PM Noda: A Week of Political Drama and the Challenge Ahead