Sorry, I don't have a source for this.
Making common cause with people with whom one disagrees about many other issues is a natural state of affairs for most libertarians. Since we are such a minority, we can only make progress seeking out allies on the Left and Right on particular issues. It was so natural to me that I was caught short when I ran Equal Marriage Arizona to find that many other people have no desire to do this. They will not make common cause with you on an issue with which they agree with you 100% if they disagree with you on an array of unrelated issues. I have now come to the conclusion that the latter attitude is more common than the former. The problem with politics is, IMO, not the lack of compromise, but this lack of ability to make common cause across political lines on narrow issues. Thus, for example, Elizabeth Warren is unable to make common cause with Republicans on the Ex-Im Bank, despite the fact it hits on two of her hot buttons (corporate subsidies and crony insider benefits for Wall Street bankers).