There is a reason that no geologists or engineers have endorsed the ideal of explosives... it would make a bad situation infinitely worse.

First, a little background:

The ideal was born from Soviet attempts at killing blowouts in gas wells in Kazakhstan back in the 60s. They attempted to kill 5 wells with nuclear devices, and succeeded in stopping the flow(of gas) in 4 of those.

That is a 20% fail rate-not very good! Thus far, in over 150 years of drilling, relief wells have been 100% successful. Hell, even the Soviets abandoned the practice when they realized the clusterfuck that could be unleashed. Here is a video of a 100m collapse structure that has been burning for 40 years in Kazakhstan: Door To Hell!

It took several months to drill the well, and fabricate a device that could be "pushed" down the hole. The nukes available aren't small enough to fit into a well bore.

One must remember that the Soviet attempts were on gas wells- not oil wells- and it was performed on land- not a mile below water. Too, the strata was hard(well indurated), and a shale horizon was found in which to detonate the device. The strata in the Gulf of Mexico(GoM) are poorly consolidated clastics and turbidites(think underwater mud slides)

The strata in the GoM are also permeated with salt domes(diapirs), sheets, thrusts, and when they are exposed to heat, they melt and flow. All of the structural features in the GoM are associated with movement of the salt... they are very plastic.

Some problems:

For the sake of argument, let us suppose that a nuclear device is detonated at some distance below the surface(I will ignore the diapirs, radioactivity, psunamis, and the other obvious stuff). When seismic waves pass through unconsolidated clastics(calcilutites, calcisiltites, calcarenites, turbidites-which is what the GoM sediments are composed of), those sediments are severly deformed.

Here is a photo of the deformation that resulted from a relatively small  earthquake about 465 million years ago in unconsolidated clastics:

Eat up, huh? That structure has been mapped for several hundred Km²! Now, I don't know what sits on the bottom of the GoM, but anything sitting down there within 50-100km would be affected.

Though, a more pressing problem would be communication of fluids between various beds of strata at different locations and elevations. When the blast is detonated, it will create cracks(joints) in the rock at depth.

The deeper one goes into the rock column, the more indurated the sediments become... they are older, and have been exposed to more heat and pressure. Too the deeper, the more the pressure. Think of it like this- how much does one cubic foot of rock weigh? Now, think about that one cubic foot but instead, it is now 1 foot by 1 foot by 2 miles!!! That is a shit load of pressure(it works out to about 12000psi)!

Ok, so you set the device off and cracks form. Well, there are other formations in the immediate vicinity that are producing oil. Suddenly, some of the formations higher up in the rock column(that are under less pressure) receive communication with some of the deeper formations.

Those deeper formation's pressure is now communicated to the shallower formations. The wells in that formation "kick", and now we have multiple blow outs...

See where this is going? A bad situation a hell of a lot worse.

As to your paragraph, I agree.

There is a clear indication that the BP top man was over his head. He has admitted, under penalty of purjury, that he was there to learn "deep water".

As to your second-what the fuck can to fed do other fuck up a bad situation?

A few more thoughts: to those that think that Obama is twiddling thumbs. There isn't shit the feds can do in this situation; they don't have the technical expertise, or the equipment.
Besides, do you really want the fuckers that give you public schools and the DMV to be in control? I know that I don't!

Though, they do oversee some areas, for instance, it was administrative concerns that led to the top kill being suspended. There was no way it could have worked, and it very really could have made a bad situation much worse. The top parts of the casement are 36" pipe with the production string encased within. It is clear that the blow out occurred because the final cement job on the seal between the production casing and the casement failed at the base of the well. This meant that oil and gas were flowing up the space in between(the annulus) and that that had compromised some of the seals where the production string was "hanging" from the pip above.

As the string goes deeper, the diameter becomes less, and the pipe below is "hung" from the one above. The top of the casement isn't meant to withstand the higher pressures. So, if the mud from the top kill had of found its way into the casement-at pressure-there could have been a blow out below the surface.
That would have been real bad! Same scenario as above where you have formation pressure at the surface!!!

It was the administration that stopped this dangerous window dressing that was "Top Kill".

Best hopes for now are for the LMRP(top hat) solution. It has a good chance at getting most of the oil. But rest assured, this thing will blow until it can be bottom killed when the relief well is completed.