It's not clear whether federal prosecutors ever took seriously a terrorism plot, foiled last year, to blow up the Pentagon using model planes, but on Tuesday they were poised to get a serious conviction out of it as the defendant, Rezwan Ferdaus, agreed to plead guilty. In a plea bargain announced Tuesday, Ferdaus' lawyers agreed to have their client plead guilty to two of the six charges against him, and both sides would seek 17 years in prison for the Muslim-American citizen with a degree in physics from Northeastern University.

The feds have never acknowledged that the plot was far-fetched from the beginning, but they did help Ferdaus get set up to carry it out, and supplied him with inert material he thought was explosive. As The Associated Press's Denise Lavoie noted, "Counter-terrorism experts and model-aircraft enthusiasts said it would be nearly impossible to inflict large-scale damage of the kind Ferdaus allegedly envisioned using model plane because the aircraft are too small, can't carry enough explosives and are too difficult to fly." But it was Ferdaus' intentions that did him in, ABC News' D.J. Marks reports. "The Justice Department says agents gave Ferdaus every opportunity to back out of the plot, but he refused even after being warned that his attacks could kill women and children." He's expected to enter his guilty plea July 20.

[Inset photo via AP]