In this age of dampened American spirits, some look back wistfully on an earlier time when presidential contests were filtered through impartial and upstanding television anchors, such as Edward Murrow or Walter Cronkite.

Rose-tinted, or otherwise, such nostalgia is felt by a dwindling minority. Most viewers have for years been voting with their remote controls for something very different. The tastes of most of those who still get their news from news shows – a larger but also dwindling minority – could be summarised in four words: Bill O’Reilly and Keith Olbermann.

Neither O’Reilly (pictured below left), the Fox News host who is arguably the most influential conservative on television, nor Olbermann (below right), the anchor of MSNBC’s Countdown, who has become O’Reilly’s liberal counterpart, are impartial chroniclers of the 2008 election.

In the right corner, O’Reilly uses his nightly one-hour show to harangue the liberal “loons”, “radical Marxists” and “leftwing nuts” who supposedly stand behind the Democratic nominee. Aided by a phalanx of glamorous conservative cult figures, such as Ann Coulter, who described the 2004 Democratic convention as the “Spawn of Satan”, and Laura Ingraham, a former speechwriter for Ronald Reagan, O’Reilly is rarely out of the news himself.

Earlier this year he appeared to threaten Michelle Obama after she had said that for the first time in her life she was proud of America (because of her husband’s success). O’Reilly did not offer a straight apology for the following remarks: “I don’t want to go on a lynching party against Michelle Obama unless there’s evidence, hard facts, that say this is how the woman really feels,” said O’Reilly. “If that’s how she really feels...we’ll track it down.”

Although free of Ku Klux Klan imagery, Olbermann is no less pointed. In his “Special Comment” – an on-air editorial on his nightly one-hour show – Olbermann gives his own, inimitably adjectival version of what’s what. In one recent edition, he took the Republican nominee to task for having complained of bias at NBC, the parent channel of MSNBC: “Despite how you have whined, Senator McCain, you have no entitlement to only sycophantic, deceptive, air-brushed coverage in the media. And despite how you have strutted, Senator McCain, you have no God-given right to the presidency.”

But Olbermann and O’Reilly’s most withering points of view are reserved for each other. So cantankerous is their mutual dislike that viewers could be forgiven for thinking the real 2008 election was between Countdown and the O’Reilly Factor, with McCain and Obama serving as mere props.

Describing O’Reilly, variously, as “Bill O’ the Clown”, “a lying snake oil salesman” and even the “Sisyphus of Morons”, Olbermann’s famed wordiness takes on a special sting when applied to his rival on “Fixed News”.

“Abraham Lincoln did not shoot John Wilkes Booth. Titanic did not sink a North Atlantic iceberg. And Fox News is neither fair nor balanced [the channel’s motto is “Fair and Balanced”]. These are simple historical facts intelligible to all adults, most children, and some of your more discerning domesticated animals.”

Olbermann continued: “Bill O’Reilly is the gift that keeps on giving...Nary a day passes without something being belched forth from [the man who], depending on how you look at it, either extinguishes your faith in mankind or...instead steps on the rake that he has invariably left directly in his own path.”

As the one with a much larger audience share – O’Reilly gets between 2m and 4m viewers a night, whereas Olbermann rarely tops 1m – O’Reilly never actually mentions his taunter by name. Instead, he counterposes his own “Spin-Free Zone” with the allegedly biased, liberal mainstream media that he says is epitomised by NBC and MSNBC. No insinuation is too outrageous.

In a recent show, O’Reilly came close to branding as traitors anyone who gave an airing to Russia’s point of view over the Georgia crisis. “With a network like NBC, Vladimir Putin has a fifth column right here in the good old US of A,” he said. “But most Americans understand that Putin is a villain...the question is which presidential candidate will most effectively deal with him? Yet another decision for the American voter to make.”

Claiming to be the standard-bearer of impartiality, O’Reilly continues: “We have established beyond a reasonable doubt that NBC News has taken a sharp turn to the left and it was done for two basic reasons. First, its MSNBC network is a flop...And secondly because NBC News’ entire management team are committed liberals.”

Both shows run segments lampooning figures on the other side – invariably their most cartoonish opponents. Michael Moore, the leftwing filmmaker, gets O’Reilly’s stick, while Rush Limbaugh, the conservative talk radio host, is a popular target of Olbermann’s.

Yet both can occasionally also be instructive. O’Reilly likes to teach viewers new words at the end of his show. Recent examples include “misanthrope”, “fallacious” and “churlish”. Olbermann, meanwhile, produces his own neologisms.

On occasions they can even dispense balanced advice. “Now all of this means little to you, the viewer, because you can choose who you want to watch – you can turn them off,” said O’Reilly recently after lambasting his rival channel for the umpteenth time. “What does matter is when a news organisation puts out falsehoods. And that happens all the time.”

This article is part of a series on TV around the world. For earlier pieces, visit www.ft.com/arts/tv