The Trump administration's fight to question the election's outcome is providing a massive field test of the effectiveness of online echo chambers and filter bubbles.The state of play: So far, the evidence from the Trump universe shows partisan delusion winning out over objective reality.By the numbers: Some 70% of Republicans now believe the election was not free and fair, according to a Politico/Morning Consult poll out Tuesday.That belief may be fast on its way to becoming GOP orthodoxy. A full 86% of Trump voters polled Nov. 8 to 10 didn’t believe Joe Biden had legitimately won, the Economist and YouGov found.Catch up quick: "Filter bubbles" and "echo chambers" are both names for the idea that partisans use the internet to create preferred alternate versions of truth, tuning in to strident voices on their side and ignoring contradictory information.Social networks and cable news networks show users material that aligns with their worldviews, and users in turn seek out public figures and communities to reinforce those views.Algorithms supercharge this self-segregation, learning what people like and serving up more of it.Why it matters: If millions of citizens finish the year believing — without proof or even evidence — that the rightful leader of the nation has been deposed in a coup, the U.S. could face long-term instability and a deepening crisis of legitimacy.What's happening: Facebook, Twitter, YouTube and other, smaller platforms are awash in counter-factual claims that President Trump won the election.These claims are based on unsupported allegations of voter fraud and purported evidence such as increased voter turnout among Democrats and mail-in ballots skewing strongly Democratic after Trump spent months discouraging voting by mail.They have the imprimatur of legitimacy as figures from Trump and his family to Sen. Ted Cruz to top GOP officials embrace and promote them.The platforms have worked to limit election-related misinformation by labeling false or premature claims, but the enforcement often lags the spread of lies, and the companies can only go so far in trying to shut down a political argument pursued by millions of individuals.Facebook and Google, for instance, have extended post-election political ad blackouts, but that has no impact on the continued spread of misinformation through non-paid posts.Reality check: Joe Biden's margin of victory in decisive states is too wide to be explained by fraud, which all independent observers, domestic and international, agree is rare and small-scale in the U.S.Trump's legal team, administration, media surrogates and allies in Congress have all failed to produce any evidence of their extraordinary claim that pervasive, unprecedented and undetected fraud swung the election for Biden.The other side: Just as Trump's loss took many of his supporters by surprise, ultimately driving them further into their filter bubbles, so were many Democrats caught off guard by the narrowness of the tally in many states, Trump's expansion of his vote count since 2016, and Republicans' strong showing in many down-ballot races.And there are certainly plenty of committed liberals who since 2016 have seen Russia behind every corner, treating everyone they disagree with online as a Russian bot or troll.The catch: There's a clear asymmetry in the volume of misinformation on either side and the extent to which liberals' and conservatives' filter bubbles reflect a break from reality.Between the lines: Platforms are focused on limiting the supply of misinformation, but we're living in a world where there's extraordinary demand for it, as journalism professor Jay Rosen points out.People who embrace a false election claim may know that it's untrue but promote it anyway out of tribal solidarity or self-interest. "The challenge is not that most people don’t see the truth — it’s that partisanship undermines accountability. Americans are all too willing to forgive political falsehoods from partisans on their side of the aisle," writes political scientist Brendan Nyhan. What's next: The embrace of alternate online realities can have dangerous real-world impacts, as incidents of violence connected to the QAnon conspiracy theory demonstrate.