PSL is growing as a party, organizes protests and other forms of activism, educates on theory and agitates via news programs. They have strong connections to other activist orgs like the ANSWER coalition. The fact that they do not hold seats or win elections does not mean they don't serve a function, they serve us far better than the DNC ever could despite being much smaller. They aren't a vanguard yet, but each year they grow and get closer to being one.