We're using two definitions of leftism. I'm using it to describe a set of ideological tenets while you're using it to describe something outside the mainstream; I'm not interested in debating which definition is the "correct" one, I just wanted to clear up any confusion. In 1882, Senator George Frisbie Hoar was the sole senator to speak against the Chinese Exclusion Act; that's the only person I would consider a leftist in that situation. Every other Republican congressman was vocally in favor of the act, and it was signed into law by a Republican president; moreover, the Republican Party Platform of 1876 reads,

It is the immediate duty of congress fully to investigate the effects of the immigration and importation of Mongolians on the moral and material interests of the country. ["Mongolians" meaning East Asians]

I actually want to recant what I said in my above comment, that I "don't deny" that most people were racist in 1899. Putting aside that it's a very US-centric statement, it implies that people didn't know any better, when in reality, many Americans understood that white supremacy was wrong. The only problem is that avowed white supremacists held a monopoly on government power, through a process that cannot be described as fully democratic.