When “concerned” Republicans offer “advice” to Democrats, it’s simple: Democrats should never listen. Ever.

Back in November, Democrats and Republicans squared off over the wildly popular State Children’s Health Insurance Program (SCHIP). Polls and momentum were clearly in the Democrats’ favor, yet House Minority Leader John Boehner (R-Ohio) felt the need to express his deep “concern”: “Democrats are making a strategic miscalculation here.”

The idea of Republicans offering strategic advice to Democrats is, quite frankly, absurd. If high-profile Democratic efforts to bolster SCHIP were truly such a strategic miscalculation, Republicans surely would’ve kept silent and let Democrats damage themselves.

In the blog world we call this “concern trolling” — offering a poisoned apple in the form of advice to political opponents that, if taken, would harm the recipient. Republicans, and their allies in the media, are past masters.

As Democrats fought the Iraq supplementals in 2007, “one GOP aide characterized the Democrats’ decision as a ‘gift’ that would backfire politically on the Democrats.” David Broder, whose concern trolling on behalf of the D.C. conservative establishment is unrivaled in its longevity and schoolmarmish tone, fretted that, “The danger may be greatest for the Democrats, even though President Bush’s failings have put them in a favored position to win the next election.”

Magnified by the Beltway echo chamber, this concern trolling led to many Democratic capitulations on Iraq despite continued massive opposition to the war. The result has been a Congress less popular than even Bush.

But when Democrats have resisted the concern troll bait, they’ve reaped rewards. During the 2005 Bush administration attempt to privatize Social Security, Council of Economic Advisers Chairman Greg Mankiw wrote — in the ironically titled opinion piece “Free Advice to Democrats” — “Some members of your party want to deny that we need to fix Social Security. Let’s face it: When you do this, you look like idiots … even if you win that argument, you lose. You look like you’re more interested in word games than good policy.”

The National Review’s Stanley Kurtz wrote, “Every year, the voltage running through the third rail of Social Security politics grows weaker. Sooner or later, the Democrats’ little venture in nostalgia politics is going to bite back on them.” And the ever-concerned Broder sniffed that Democrats were “putting politics above the national interest” by refusing to deal with Republicans intent on destroying the cornerstone of American retirement security.

It was the rejection of such “advice” that gave Democrats one of their first substantive policy victories against Bush, dramatically boosted the popularity of congressional Democrats, damaged Bush in the polls and set the stage for the 2006 elections. Not to mention that the rejection of the concern trolls saved Social Security for millions of working Americans.

Note that the “concern” cuts only one way. Perhaps it’s lack of opportunities — concern trolling is based on scaring away the opposition from taking action or advocating positions popular with the broader electorate. But Republicans haven’t done much that is popular with a majority of the country. Are Democrats going to scare them away from trying to privatize Social Security? From supporting a deeply unpopular war? From demonizing the Northeast to the point their party faces near-extinction in the region?

Clearly, Democrats understand that they’re not in the business of giving their opponents advice. What they need to remember is that they shouldn’t be in the business of taking it, either.

Moulitsas is founder and publisher of Daily Kos (www.dailykos.com ).