"Trust me"

Here's a good question:

Today's question: Who do you trust?

What struck me about the Elena Kagan nomination is that essentially for liberals it was a question of trust.  There was, famously, little record to go on...except that Barack Obama, Joe Biden, and Bill Clinton had all worked with her and supported her career and her nomination (well, you could also deduce her beliefs based on her cultural background, as many supporters and opponents did, but I'll leave that aside for now).  For a lot of Democrats, that was sufficient; for a minority, it clearly wasn't.  But the Kagan nomination is hardly unique.  Whether it's the question of what will happen over time in Iraq and Afghanistan, or whether Obama negotiated the best deal he could on various bills, or whether obscure provisions of some laws are consistent or not with liberal principles, most of the time, for most people, it comes down to either trusting supporters or trusting skeptics.  It comes up, too, for activists choosing which candidate to support in primary elections, or choosing which organization to support.  Of course, with all of these things, one option is to research it yourself...but even then, that often means trusting someone else's summary of research, and at any rate no one can research every issue, every nominee, every candidate by themselves.

So my question is: who do you trust?  Are there specific pols, interest group leaders, activists, pundits, or whoever who, if they support a candidate or a nominee or a bill, you would basically assume that she or it was acceptably liberal?