Some historians speculate that if the Progressive Party had run only the Roosevelt presidential ticket, it might have attracted many more Republicans willing to split their ballot, but the progressive movement was strongest at the state level and so the new party had fielded candidates for governor and state legislature. In Pittsburgh, Pennsylvania, the local Republican boss, at odds with state party leaders, joined Roosevelt's cause. In spite of this, about 250 Progressives were elected to local offices. The Democrats gained many state legislature seats, which gave them 10 additional U.S. Senate seats—they also gained 63 U.S. House seats.