You can almost read Politico’s Charles Mahtesian and Jim VandeHei as writing in dialogue with political scientists Thomas Mann and Norman Ornstein. But whereas Mann and Ornstein blame the Republican Party for the extreme polarization and institutional dysfunction of the last several years, Mahtesian and VandeHei repeat the common Beltway lament—by allowing voters on the “far left” and “far right” to oust Blue Dog Democrats and centrist Republicans, both parties are responsible for Congressional polarization.

By virtue of its even-handedness, the Politico argument sounds more plausible, but—unfortunately—it also runs counter to all available evidence. Indeed, this is where Mann and Ornstein succeed; they gather evidence from the last thirty years of political history to show two things. First, that the Republican Party has veered sharply to the right, in a way that wasn’t mirrored by Demorats; and second, that the Republican Party has abandoned any commitment to existing rules or institutional norms. From the filibuster to the confirmation process, the GOP has abused the rules of Congress to stop or nullify laws passed by Democrats.

None of this factors into the Politico analysis. Instead, we get hoary old clichés about the nobility of centrist lawmakers, complaints about outside groups and an attempt to draw equivalence between ideological extremes on both sides, as if the “far left” has any kind of influence in the contemporary Democratic Party, much less liberal politics writ large. Here are a few of the most egregious parts of Politico’s analysis.

On the disappearance of Senate moderates:

The Senate, once the chamber of deliberation and reason, is getting its own extreme makeover. Moderates such as Maine Republican Olympia Snowe and Democrat Ben Nelson are bolting an institution that barely resembles the one they entered as idealistic deal-makers.

The tell here is the phrase “idealistic deal-makers,” which is a contradiction in terms. The defining feature of Senate centrists has been their categorical commitment to the “deal” and complete blindness to any broader principle. Ben Nelson agreed to allow an up-or-down vote on healthcare reform only in return for preferential Medicaid funding for his home state. Olympia Snowe voted for healthcare reform when it was in committee but quickly withdrew her vote after pressue from Republican leaders. Other centrist senators, like Joe Lieberman or Evan Byah, were equal in their political posturing, attacking the administration for attempting to pass an ambitious piece of legislation.

On the apparent power of the “far left”:

Centrist Democrats got that memo in 2010—they saw how labor almost took down Sen. Blanche Lincoln, who ended up getting crushed in November anyway. That’s just the Senate.

In the House, where the conservative Democrats known as the Blue Dogs saw their numbers cut in half in 2010, the climate isn’t much different. Five of the remaining Blue Dogs have already announced their intention to retire; two more lost re-election bids last Tuesday in Pennsylvania.

Among their sins: Departing from the party line to vote against the president’s healthcare plan.

It says something about the success of Republican messaging that a healthcare bill nearly identical to the one crafted by Mitt Romney in Massachusetts can become intolerably liberal once Democrats decide to support it. That said, the Blue Dog massacre of 2010 had more to do with Republican wins then it did with any Democratic purge. Blue Dogs suffered in the midterms because they represented Republican districts in a year where the Republican wave was huge. To blame this on the “left” is insane. Likewise, Blanche Lincoln was actively working against her constituents in Arkansas; is it somehow unacceptable for voters to oppose a senator if he or she is a “centrist”? Mahtesian and VandeHei are clearly filled with contempt voters, and it shows throughout the piece.

Both points get to the biggest problems with Mahtesian and VandeHei’s take on the sources of polarization in Congress. Leftists have little influence in the United States, and liberals are a junior partner in the Democratic coalition. Their interests are often overlooked, and their political strategies are often ignored or disparaged by Democratic politicians (see: the Obama administration). By contrast, movement conservatives have a firm grip on every level of the Republican Party—there’s literally no room for success in the GOP if you do not pledge fealty to right-wing orthodoxy. The equivalent simply isn’t true among Democrats.

There is a dramatic asymmetry in American politics; at the same time that Democrats are working to preserve the basics of the status quo, Republicans are pushing to transform our traditional commitments to public investment, research and the least-well-off. The contrast isn’t hard to grok; Barack Obama’s plan for the next decade of domestic policy is to implement the Affordable Care Act—a reorganization of the private health insurance market based on bipartisan ideas—and return tax rates on the wealthy to where they were under the Clinton administration.

The GOP’s plan, on the other hand, calls for the permanent extension of the Bush tax cuts, further cuts on high earners, a cap on the federal budget and dramatic cuts to non-defense discretionary spending. To call this “conservative” is to ignore the plain meaning of the word; this is a radical change to the federal government.

Mahtesian, VandeHei and many others notwithstanding, there is no ideological balance in American politics. To pretend otherwise is to willfully mislead readers in the service of a flawed “objectivity.”