This is what I would say:
“The Republican Party is more right-wing, or more conservative. This means that they believe in traditional, often religious-based social values e.g. opposed to abortion, lukewarm on LGBT rights and anti-gun control, and that they believe the government shouldn’t interfere in the economy and people should take responsibility for their own situation e.g. they support low taxes, fewer regulations on business and are against healthcare as a right for all.
“The Democratic is left-of-centre, or liberal. They are more inclined to be tolerant on social issues i.e. let people do what they want as long as it isn’t hurting people, so they support a woman’s right to choose an abortion, LGBT rights and are more pro-drug legalisation than the Republicans. They also believe that government has a role to play in helping people and ensuring a fairer economy, so they support higher taxes on the wealthy, regulations on business and the government providing some sort of healthcare for those who can’t afford it.”
