Democrats are understandably obsessed with Darrell Issa — he’s built himself up as a one-man investigative machine aimed straight at the Obama presidency. But a handful of liberal political operatives in California — including a former Hillary Clinton hand — are taking their anti-Issa passion to a whole new level, launching a nonprofit group, a website and even paid media advertisements aimed at undermining and investigating the rabble-rousing chairman of the House Oversight and Government Reform Committee. They say they’re leaving no stone unturned in digging into Issa’s personal and business history. This week, the group will reveal more than...