Is there an equivalent US political party to the UK's Labour Party? If so, what is it?
Not entirely. The US has a major disadvantage in such direct comparisons because of its two party system. So I think a better question would be to ask whether there is a certain faction of a US political party which is closer to Labour Party policy. The left of the Democratic Party would represent a Labour mainstream, with the Bernie Sanders followers being akin to the solid-Left politics of Jeremy Corbyn. From there you would have the 'centrist' Democrats who are akin to the Liberal Democrats and the conservative 'Blue Dogs' possibly being akin to the Conservative Party along with very moderate Republicans. So, no. There is no direct equivalent in political party terms, but there are certainly factions who agree with their policies ans intentions at least on a relative basis. The US and UK political scenarios are very different so any such comparison would have to be on a relative basis, such as if I were to compare the Tea Party to UKIP (as I did in my undergraduate dissertation).
Why do you support the democrats or republicans?
Why do you support the political party that you choose. Do you agree with all their views? I can't agree fully with either party. I seem to have this ability to make up my own mind as to which position I take toward things. Like take for instance welfare. I think we need to support those who really need it like the elderly and handicapped, but those who don't are abusing the system and it needs to be revamped. So what I am really wondering is how the die hard whatever party members on here that just bash the other party decide which party they are going to support.