Political opportunities are the most important aspect of PPT, because according to the theory, without them, success for a social movement is impossible. Political opportunities--or opportunities for intervention and change within the existing political system--exist when the system experiences vulnerabilities. Vulnerabilities in the system can arise for a variety of reasons, but hinge on a crisis of legitimacy wherein the populace no longer supports the social and economic conditions fostered or maintained by the system. Opportunities might be driven by the broadening of political enfranchisement to those previously excluded (like women and people of color, historically speaking), divisions among leaders, increasing diversity within political bodies and the electorate, and a loosening of repressive structures that previously kept people from demanding change.