TWO YEARS AFTER 9/11, a clutch of Off Broadway plays reveals American dramatists still grappling with ways to address the event. It’s perhaps not a surprise. As the US writer Joyce Carol Oates noted during the initial aftermath, just as no serious fiction can be set in the first half of the 1940s without reflecting the Second World War, so realistic American writing about contemporary issues cannot help but acknowledge that the World Trade Centre no longer stands.

The earliest stage responses to September 11 were straightforward expressions of grief, such as Anne Nelson’s The Guys, in which a journalist helps a New York City fire captain to compose eulogies for his lost comrades at the twin towers. Then came irony with plays focusing on personal dramas in the face of the tragedy. Notable was Neil LaBute’s The Mercy Seat, which makes its British debut at the Almeida in London this week. In this acerbic two-hander, a married man was meant to be at the World Trade Centre on the fateful day but was visiting his mistress instead.

Of the new post-9/11 plays in New York, Jonathan Bell’s Portraits is the most conventional. After the attacks, Bell compulsively collected September 11-related articles, which he later adapted into monologues for fictional figures (including another philandering husband) touched by the attacks in various ways. The playwright wanted Portraits to “help people have some kind of remembrance and resolution to the whole thing”, but its short-lived run suggests that New York audiences have grown overfamiliar with the lecture truisms and news clips spouted by Bell’s speakers.

Like many September 11 pieces, the memorial-service-posing-as-art response has quickly grown stale and inadequate. So post-9/11 plays are moving on, trying to lift the event into a new realm through comedy, satire and metaphysics.

Take Craig Wright’s Recent Tragic Events, which marks the New York stage debut of Boogie Nights actress Heather Graham. She plays a Minneapolis ad executive who goes through with an awkward blind date on September 12, 2001, while waiting for news about her missing sister in Manhattan.

Wright, part of the writing team for the quirkily dark TV series Six Feet Under, has said that he wrote the play out of frustration “at the way the media was able to so quickly and handily turn the events into a very specific narrative that precluded other interpretations”. But in striving for a cosmic perspective, complete with an omniscient stage manager figure and even Joyce Carol Oates (in the form of a glove puppet), the play becomes an unwieldy mixture of sitcom-on-a-sofa humour and musings on fate, free will and facing tragedy.

A more combustible mix of Shavian debate and social satire is Alexandra Gersten-Vassilaros and Theresa Rebeck’s Omnium Gatherum (cod-Latin for a motley group of people). Set during a chic dinner party in Hell with a Martha Stewart-like hostess, the play raises such thorny issues as whether peace can ever exist and whether US policies somehow justified the terrorists’ actions on September 11.

Rebeck told the New York Times how she had watched the talk shows and “CNN with all those pundits trying to squeeze meaning out of what was for us clearly an unknowable event”. Gersten-Vassilaros was also intrigued how the situation went from deep tragedy to surreal absurdity, with “CNN interviewing someone who lost a relative in the towers and then they’d cut to a commercial with a smile on their face”.

It’s no surprise, then, that the play’s dinner guests are loosely based on such warring talking heads as gadfly commentator Christopher Hitchens, pro-war thriller writer Tom Clancy and the late Middle East expert Edward Said. But the play’s authors face the problem of trying to make dialectic interesting, especially when the post-9/11 TV punditry that they’re sending up has almost rendered this kind of argument play obsolete.

While Gersten-Vassilaros and Rebeck were inspired by the post-9/11 media coverage, the inspiration for The Mercy Seat was also once removed from the event itself. Neil LaBute, whose caustic portraits of casual cruelty include Bash, The Shape of Things and In the Company of Men, was in Chicago trying to get to Manhattan for a play rehearsal when the planes slammed into the towers. What should have been a short plane trip became a 21-hour marathon.

LaBute recalls a fleeting, regretful moment when he arrived at the train station: “I found this huge line of people. I thought: ‘Wow, I know it’s terrible, but this is really inconvenient.’ It made me think how people don’t always do the right thing. I wanted to examine how selfishness can still exist during a moment of national selflessness”.

The Mercy Seat, directed in London by Michael Attenborough, has adulterers Ben (John Hannah) and his boss Abby (Sinead Cusack) missing the 9/11 catastrophe because they were in her flat at the time. The day after, we find them dissecting their relationship and Ben even contemplating using the tragedy to abandon his wife and kids — hardly the stuff of heroism, so often (too often, maybe) the theme of art made in the shadow of the terrorist attacks.

“Do you honestly think we are not gonna rebound from this?” Ben asks in the play. “And I don’t just mean you and me, I’m saying the country as a whole. Of course we will. We’ll do what it takes, go after whomever we need to, call out the tanks and s***, but we’re gonna have the World Series, and Christmas, and all the other crap that you can count on in life . . . I’m saying the American way is to overcome, to conquer, to come out on top.”

LaBute admits that when the play was first seen in New York last December, with Sigourney Weaver and Live Schreiber, some Manhattan audiences weren’t ready for such an attitude. But the second anniversary of September 11 saw US television and other media scaling down their remembrances and there’s now a sense that the event is beginning to settle into history.

What’s telling, though, about America’s post-9/11 plays is the way they address the event from an oblique distance, as if it remains dauntingly incomprehensible. Recent Tragic Events is an absurdist romantic comedy set in Minneapolis, not New York. The monologues in Portraits are framed by an artist struggling to create 9/11’s Guernica. Gersten-Vassilaros says that Omnium Gatherum is “a play about questions, not September 11 ”. LaBute regards The Mercy Seat as “a play about relationships, not 9/11”.

Perhaps that’s simply the American dramatists’ way. Think of Arthur Miller’s The Crucible, which tackled the McCarthy witch-hunts in the guise of the Salem witch trials, or even this year’s Dirty Story by John Patrick Shanley, which dealt with the Israeli-Palestinian conflict as represented by a dysfunctional romantic relationship. Maybe this current theatre of the unnerved simply needs more time to tackle 9/11 head on.

For now, it seems as if US dramatists are only able to express what Ben feels near the end of The Mercy Seat: “I’m just a little lost right now.”

• The Mercy Seat is in preview and opens on Thursday at the Almeida, N1 (020-7359 4404)