I think the Americanism for that would be Progressive

No it's not, because personal politics aren't pure embodiments of monolithic ideologies. It's a shorthand for a political perspective that incorporates aspects of both liberalism and leftism.

"Liberal" is an oxymoron. The social contract is not optional. We agree to be bound by rules because we prefer it to being by force, which is the default. Security is liberty, in the optimization sense.