I don't consider myself "liberal". To me that means you consider that one can do anything they want (similar to Libertarian). I think of myself more as "progressive". I hesitate to use the word "believe" because that suggests things accepted without facts. Let's just says I "think" some things based on evidence.
There are many issues in politics today. When you get down to the basics, the disagreements are mostly about the role of government. I think that government is a positive thing.
Federalist Paper #1 said "It has been frequently remarked, that it seems to have been reserved to
the people of this country, by their conduct and example, to decide the
important question, whether societies of men are really capable or not,
of establishing good government from reflection and choice, or whether
they are forever destined to depend, for their political constitutions,
on accident and force".
Therefore, representative government itself is a positive good. We have good roads, and government efforts have created those. We have an educated population and government-created public schools have done that. We have government regulations to keep unscrupulous and greedy people in check.
So Government is a generally positive benefit to society. Some people disagree. I disagree with them. I positively WANT an active government to coordinate the improvement of life for all the populace. That's what governance IS! Governance is NOT trying to kill all actions, stopping all improvements to life, or just saying "NO" everday to managing the nations affairs.
The progress of society has been from Kings to Representative Democracy (my apologies to the utopian Karl Marx). The more representative governance is, the better.
If I "believe" in anything, it is actively beneficial governance for all.