President Bartlet’s White House isn’t quite the alluring and mysterious realm it once was. It used to play host to one of the most unmissable, unforgettable series on television. Now its most celebrated elements – layer upon layer of characterisation and narrative meticulously stitched together and carefully mapped out minute by minute – have started to peel away in an alarmingly undisciplined fashion.

The West Wing is in a trough. At the moment it reels wildly between any one of a dozen or so concerns, which themselves no longer take the form of thought-provoking expositions or craftily paced arguments but instead resemble almost lazy and half-defined efforts at point-scoring or shooting at open goals. What used to be an ever-present atmosphere of rigorously plotted tension and menace has ended up dispersed amidst great blundering plot revelations and, perhaps most unlikely of all, sickly emotional outpourings. It’s all a very long way from what this programme was doing just a couple of years ago, when it made merry with clichés and conventions in an audaciously blatant fashion and rustled up some of the most unpredictable TV drama around.

The decline has not been sudden. For some time now the show has dared viewers to accept it has the right to take itself off on tangents of its own choosing, even if that means virtually ignoring all the foundational work put in to date to create a palette of challenging, exciting people and ideas. The key moment was the climax to the second series, shown in this country on Channel 4 just 12 months ago. This took the form of an almost operatic mix of grand locations and tortured self-expression, and ended up such a devastating sensory ride you sort of wanted it to go on for ever – a spiral of enticing implications and speculations that needed no resolution. Everything was funnelled towards a final dénouement, where the President was scheduled to announce if, in the light of confirming his hitherto-secret Multiple Sclerosis, he was to run for a second term in office. Lightning flashed, crowds jostled, faces were flushed. The camera faded on Bartlet about to deliver his answer.

You kind of hoped there was the outside chance the show’s creators would defy probability and condemn The West Wing to a brutally short-term life span. As it was the near-inevitable happened, and so began the long haul towards re-election. This week’s episode, a whole series and a half later, marked the arrival at long last of polling day and the cue for what could’ve been another watershed moment in the programme’s history. But instead of a mouth-watering epic of, say, bleak political realism and thrilling personal confession, all we got was a deeply unsatisfying jamboree curiously devoid of feeling that really made you sorry Bartlet had, by the end of it all, won.

It’s now clear the business of driving the show to that point where Bartlet had to say publicly he’d run for office again, rather than the matter of him actually saying it, actually conspired to help tip The West Wing into such a precarious state. The episodes immediately in the aftermath of his declaration smacked of a feeling akin to that of being winded: on the back foot, unnaturally disabled, incoherent. It felt like all the energy invested in levering the programme up to one particular point of dramatic consequence – and a fantastic one at that – meant there was nothing left in reserve to follow through with anything of note, let alone sustain that same level of exhilaration.

In turn along came a messy procession of new spin doctor-esque characters that were never properly introduced, and plotlines that spun off into dark corners rarely to be seen again. Rather than the broad sweeping canvas of series two, or even the neat, perfectly-formed playlets of series one, The West Wing did something it had never ever done before: rambled. Scripts felt untidy and last minute. Characters behaved implausibly for a bunch of people that’d been on TV almost non-stop for two years. What substance there was within episodes was repeatedly obscured by side-stories involving staff relationships and endless personality clashes, rather than, as once had been the case, going hand in hand with illuminating, enhancing secondary subplots.

Again, the very fact all this was going on, and being allowed to go on by the programme’s famously protective production team, was the most curious dilemma of all. The West Wing has always been unpredictable – indeed, a playful manipulation of a viewer’s preconceptions of life inside the White House has remained perhaps the show’s one enduring defining quality. But you never dreamed proceedings would veer so far off the rails as it came to do towards the end of series three (aired on Channel 4 earlier this year), with all trace of the trademark big political picture exchanged for endless scenes of the previously steely press secretary CJ Craig debating the contents of her wardrobe, and the sight of the erstwhile rakish deputy chief of staff Josh Lyman squabbling with his girlfriend amongst the bedclothes.

The upshot was that, until this week, what had been earlier been established as the notional fulcrum of The West Wing‘s existence – a capable President under threat from afflictions not of his own making – disappeared completely. Now, at the point of his re-election, that same scenario has finally been re-introduced, but almost as an afterthought. We saw a couple of moments where Bartlet’s hands started shaking, and his secretary dropping hints about him not being able to remember who he’s phoned. It was useful to be reminded of the President’s condition, and how it might manifest itself more forcefully in years to come. But the almost throwaway manner in which it was done compounded the feeling that here was a programme brought sadly low by a lack of focus, a wayward script and the absence of any sense the show’s makers know just what they want their characters to be doing in the next scene, let alone the next episode.

Even with a subject like a national election to play with, The West Wing can’t seem to rekindle the fire and energy of its earlier years. With the Republican opposition having virtually conceded defeat in last week’s story, all that was left was to see how the Bartlet team adapted to the responsibilities of four more years in office. Would we get a study of triumph out of adversity, or a sober meditation on the awesome task that lay ahead? As it turned out, neither. The team didn’t even seem that bothered, and by extension it was desperately hard to feel that enthused or even mildly interested by the implications of what was happening on screen.

Despite all this the outlook isn’t entirely gloomy. Not only did this episode deliver The West Wing a second term, it also planted the seed for Rob Lowe’s departure from the cast. With his character off to become a congressman in California, hopefully his former colleagues will be able to benefit from not being constantly upstaged and undercut in every other scene. As for Lowe’s replacement, the omens look good: a nerdy campaign manager with the requisite predilection for talking insanely fast but with a depth and humanism his predecessor never had. The dull anonymous spin doctors have also disappeared, plus there’s evidence the show’s recovered some of its wit, demonstrated chiefly in a nicely staged pre-title sequence depicting Josh visiting a polling booth and being accosted by a host of Democrat voters who’d all spoiled their ballot papers, but who in reality were an acting troupe hired by communications director Toby Ziegler as a practical joke.

The show’s not beyond salvaging, then, nor is it in any way cursed by a cast who get lost amongst the deluge of words and contrary plot twists. If anything the reverse is true, with the actors often going a long way to save the series from the kind of slow-motion dismemberment you feel is only just around the corner. Still, the prospect of what happens next is both intriguing and unsettling – after all, the possibility that you’re about to watch one of your favourite TV dramas unravel into an embarrassing amateurish free-for-all before your eyes doesn’t exactly make tuning in an experience to relish. So The West Wing remains a programme with which to keep a regular appointment, albeit more out of routine than respect. Besides, you never quite know where it will dare to go next. John Goodman joins the cast in a few months time. To find out just what on earth that’s all about is, in itself, worth one hour of your time every week.