Watching Mayor McGinn and his anti-tunnel partisans laboriously stoke fears of "cost overruns" is like watching racist Tea Partiers complain about budget deficits and socialism. It's kinda obvious what their real issue is, but they've fastened on some other concerns that they think can get more traction.Seattleites do not want to reopen the tunnel debate. Even McGinn knows that, which is why he did the infamous last-minute flip-flop that made his election possible. So the problem: how to sow opposition to the tunnel while not owning up to your real intentions? I know—socialism! I mean, overruns!What makes the overrun-mongers, such as the Sierra Club, so hard to take seriously is that they're generally the same crowd who've been most enthusiastic about Sound Transit's light rail—which is pretty much the cost-overrun project par excellence in recent history. (In brief, a Phase I project that was supposed to cost $5 billion over 10 years has ended up costing three times that over 25.)And those light-rail overruns were hardly driven by tunneling problems alone. Even surface construction along Martin Luther King Way was a sinkhole of delays, redos, and busted budgets. Under Sound Transit's "sub-area equity" policies, Seattle taxpayers have footed the bill for all those Seattle overruns.But no one among the anti-tunnel crowd raised any protest. Nor did their overrun anxiety manifest itself back in 2008, when Sound Transit proposed to expand northward from Husky Stadium to the Roosevelt neighborhood with a pair of two-mile-long bored tunnels. (Voters approved the plan.)It's clear that what the Sierra Club, McGinn, and all the rest of the overrun crew really mean is this: We need to be very concerned about the possibility of overruns whenever it's a project we don't like.