How do you stop a leaking oil well nearly two kilometers beneath the surface of the Gulf of Mexico? The latest effort, following the insert that siphoned some fraction of the gushing petroleum, will be to pump a mixture of thick drilling mud into the well in an attempt to stop it up like clogging a toilet. BP itself gives the operation a roughly 60 percent chance of working and hopes to undertake it on May 26.

This is the same method that stopped the most recent similar oil spill this past November—a gushing deep water well in the Timor Sea near Australia—after four tries. It will be a delicate procedure, as evidenced by the laborious (and clumsy) preparations of the underwater robots.

If all else fails, or this effort doesn't stop all the oil, it may be followed by the cunningly named "junk shot," stuffing tires, golf balls and other detritus into the well to further plug it up.

Regardless, this well will not be well and truly "killed" until another well is drilled to intersect it and permanently cap the gusher, an effort that will probably take until at least August. Obviously, it is already too late to avoid some of the worst impacts to birds and other wildlife as well as the Gulf Coast wetlands they call home as oil is already beginning to coast the marshes and beaches of Louisiana. Unfortunately, that's a kill we know will work.