And why does Bush feel he needs to effect regime change in Iran? Because of pressure by the Likudniks, here and abroad.
"Israel has drawn a red line that says, not only will they not tolerate a nuclear weapons program in Iran, they will not tolerate anything dealing with nuclear energy, especially enrichment, that could be used in a nuclear program.
So, even if Iran is telling the truth – Iran says, 'We have no nuclear weapons program. We just want peaceful nuclear energy'– Israel says, 'So long as Iran has any enrichment capability, this constitutes a threat to Israel,' and they are pressuring the United States to take forceful action."