In mid-1857 a vote was held in Kansas in which only 2,000 (out of 24,000 eligible voters) participated. In this election, the _____ was adopted, which allowed slavery in the territory. Because of many irregularities, Congress required another vote in which slavery was defeated and Kansas remained a territory. This incident, along with prior violence in Kansas, demonstrated the impossibility of deciding slavery by _____ as had been proposed by Senator Lewis Cass.