What is a liberal?

Cass Sunstein, a professor at Harvard Law School writing at The New York Times, defines liberalism in 34 points:

1. “Liberals believe in six things: freedom, human rights, pluralism, security, the rule of law and democracy.”
2. “Liberalism does not mean ‘left’ or ‘right.'”
3. Abraham Lincoln was a liberal.
4. “Rejecting despotism, liberals prize the idea of personal agency.”
5. Liberals do not like tribalism.
6. “The rule of law is central to liberalism.”
7. “Liberals believe in freedom from fear.”
8. “Liberals are aware that all over the globe, liberalism is under assault.” 
9. “Liberal authoritarianism is an oxymoron.” 
10. “Liberals believe that freedom of speech is essential to self-government.” 
11. “Liberals connect their opposition to censorship to their commitment to free and fair elections.”
12. “Liberals are committed to freedom of religion.”
13. “If postliberals or antiliberalists insist on an official religious orthodoxy, liberals will respond: Who do you think you are?”
14. “Some liberals follow Immanuel Kant, who argued that people should be treated with respect and as ends, not as mere means to the ends of others.” 
15. “Liberals prize free markets, insisting that they provide an important means by which people exercise their agency.”
16. Liberals believe in the right to private property. 
17. “Many liberals are enthusiastic about the contemporary administrative state; many liberals reject it.” 
18. “Liberals abhor the idea that life or politics is a conflict between friends and enemies.”
19. “Liberals believe that people with diverse backgrounds and views can embrace liberalism or at least certain forms of liberalism.”
20. “Liberals think that on both left and right, many antiliberals and postliberals have manufactured an opponent and called it liberalism without sufficiently engaging with the liberal tradition or actual liberal thinkers.”
21. “Liberalism is a wide tent.” 
22. “A liberal might think that Ronald Reagan was a great president and that Franklin Delano Roosevelt was an abomination; a liberal might think that Roosevelt was a great president and that Reagan was an abomination.”
23. “Liberals think that those on the left are illiberal if they are not (for example) committed to freedom of speech and viewpoint diversity.” 
24. “Liberals favor and recognize the need for a robust civil society, including a wide range of private associations that may include people who do not embrace liberalism.” 
25. “If postliberals object that free markets have serious limits and that a great deal of regulation might be justified on grounds of efficiency, redistribution or fairness, liberals are likely to say: Very possibly so.”
26. If people want the government to act in illiberal ways…liberals will stand in opposition.
27. “Some people (mostly on the left) think that because liberals believe in private property, they cannot accept redistribution or cannot prevent economic inequality from leading to political inequality.” 
28. Liberals respect tradition.
29. “Liberals do not think it adequate to say that an ideal has been in place for a long time.” 
30. “Liberals like laughter.” 
31. “Liberals believe in the public interest and the common good.”
32. “Liberals insist on the difference between liberty and license.”
33. “Liberals insist on reason giving in the public domain.”
34. “Liberals look forward as well as backward.”

See how Sunstein unpacks these points here.