I don't understand what you're arguing. Higgins said Sanders called for regime change, and then you said he was a liar for it, and then posted a link supporting the very thing he said. Unilateral US action has nothing to do with it.
Weren't we just talking about how we shouldn't be doing what Sanders says just because he's popular? Are we not able to connect the dots between the disastrous crime bill, the resulting incarceration rates, and devastation to poor and working class communities? We're going to excuse that away as a "politician with his ear to public opinion"?
The problem with this construction is that it only works in a fantasy world where everyone who is eligible to vote votes, and every voter makes a rational decision in the booth, based on the policies that the candidates are likely to support. The reality is that many people (and I'm not talking about the "class anxious" Trump voters) have been so devastated by the American economy in the last 40 years that they're no longer politically engaged. The girls behind the counter at Taco Bell, the guys that work at Home Depot. The Uber drivers that can't afford to move out of their parents' basement. The 30% of high school graduates that don't have to worry about the college debt crisis because they never went to college in the first place, and face the worst job and life prospects ever facing working class Americans.
You think these people care about climate change, Citizens United, cap gains tax rates, etc.? The problem with pushing the party further and further to the right to capture moderate Republicans that are turned off by the extremists is that it doesn't work, (they still vote Republican anyway) and it alienates your base.