By deprecating the principles of Vedic civilization and supporting cow-killing, they are immediately degraded to the platform of mlecchas and yavanas. A mleccha is a meat-eater, and a yavana is one who has deviated from Vedic culture. Unfortunately, such mlecchas and yavanas are in executive power. How, then, can there be peace and prosperity in the state? The king or the president must be the representative of the Supreme Personality of Godhead. When Maharaja Yudhisthira accepted the rule of Bharata-varsa (formerly this entire planet, including all the seas and land), he took sanction from authorities like Bhismadeva and Lord Krsna. He thus ruled the entire world according to religious principles. At the present moment, however, heads of state do not care for religious principles. If irreligious people vote on an issue, even though it be against the principles of the sastras, the bills will be passed. The president and heads of state become sinful by agreeing to such abominable activities.

From Srila Prabhupada’s purport to Cc Madhya 1.197