Left and liberal do not mean the same thing. Basically all of my blue or red friends agree with the principles of Liberalism, which brought us the enlightenment and [modern] civilization. You can ask your own friends, here's a definition:
https://en.wikipedia.org/wiki/Liberalism (quote below)
In terms of numbers, about 8% of the US population is.. left. 25% is traditional conservative. And the other 67% is regular folks who in fact agree on most policy questions
From Wikipedia:
> Liberalism is a political and moral philosophy based on liberty, consent of the governed and equality before the law. Liberals espouse a wide array of views depending on their understanding of these principles, but they generally support individual rights (including civil rights and human rights), democracy, secularism, freedom of speech, freedom of the press, freedom of religion and a market economy