Internal opposition:
1) Kurds (unpalatable to both Turkey and Iran, especially since Turkey seems intent on wiping them out at times as well)
2) Shi'ite Muslims. Unpalatable to Saudi Arabia to have another Shi'ite country in addition to Iran.
No other effective internal opposition exists, and as such we will have to do the job ourselves, so as to keep Iraq a unitary state - more of a priority than removing Saddam. The people themselves are not stupid and realise that Saddam causes their strife (he builds statues of himself while they starve), but are happy to live their lives quietly until somebody else does the job.
Iraqi threat - real, but exaggerated. Iraq will not be able to strike the US (despite what missile defence people say) for many decades yet. However Europe could be on the cards, and certainly Israel already is. Much of the drive to strike may derive from the strength of AIPAC within the US administration rather than the real threats. However is Saddam that much of a threat even with the weapons. If he uses them against Israel/Western allies he can expect a nuclear reponse and therefore would not rationally use them unless we provoke him. Note - he is not totally irrational as media portray him and reacts to threat of nuclear use by West, such as when we warned him not to use NBC weapons on our troops during Gulf War.
Should we strike?
Little justification. Although weapons of mass destruction may be in production again, amounts are FAR fewer the prior to Gulf war. Little remains from before then due to inspections that were more successful than US would have us know, but the expertese remains.
No support for war among Gulf allies, who again prefer a stable enemy rather than an Iraqi breakup. Oil flow and revenue are more important to them.
Is it all rhetoric? No, but much of it is - forcing Saddam to engage more with the world and become less of a threat than currently. We would not only be stupid to attack, but it would be highly illegal. No UN justification will simply put us at the top of the list of rogue states rather than Iraq.
But Saddam is evil I hear you say. That is as maybe, but we have supported 'evil' regimes alll over the globe. How much better is Saudi really, other than it is compliant to Western will. Look at the amount of democracy among our Gulf allies. Moral justification may provide SOME limited reason to unseat him, but the realist criterea must be taken into account as well.
What detail do you want? For more, consult Tanter, R., Rogue Regimes or I can point you towards some other references if you require.
Lucifer