I'd say one criterion by which this can be judged is whether a song sounds like a standard *when it first appears*. Blue Motel Room fits here, IMHO: even on a first hearing, it has a timelessness about it. River fits into this category too, especially with its musical quoting of Jingle Bells. The Circle Game, meanwhile, has a nursery-rhyme feel to it, which I'm sure explains its enduring popularity.
Obviously, this doesn't mean that a song which appears to have these qualities will necessarily become a standard, so I guess this measure is more of a song's *potential* to become a standard. By contrast, much as I love Hejira (understatement - it's my nfavourite song from my favourite album ever), I don't think it will ever be a standard - it's too long, too complex, the melody is too elliptical. I've probably mentioned this before, but a modern song that has a most extraordinary feel of permanence is Mary Margaret O'Hara's Keeping You In Mind, a sublime marriage of melody, arrangement and lyric which sounds for all the world as if it were a recently unearthed Cole Porter tune. It's a song that ruddy well *should* be a standard! The folk tradition is a rich source of songs that sound as old as the hills, even though they are newly minted. In the hands of a real master of the form, such as Richard Thompson or Kate Rusby, you could listen to an album and not be sure which songs were originals and which were "trad/arr". Although RT rarely records trad material these days, in the Fairport days songs like Crazy Man Michael and Farewell Farewell fitted in seamlessly with the hoary old songs of death at sea and adultery. Come to think of it, that sounds like a Nick Cave album... Azeem in London
