Again, I think that Bush is out of his depth. As the governor of Texas, he was able to do fine dealing with the Texas legislature. But Bush seems to be unble to deal with the much tougher adversaries on the national and international levels.
Regarding Congress, Bush says that the atmosphere is just too partisan and too divisive to come to any kind of accord. While there is certainly a good deal of partisanness (is that a word?) in DC, I do not think that there is inherently so much that nothing can break through. Early in his term, Bush was able to get major initiatives passed in a bi-partisan manner. It wasn't until Bush broke his promise by underfunding NCLB that the Dems started to really mistrust Bush. The blantant lies about the costs of the Medicare bill sealed the deal. Bush complains that the Dems won't work with him. It seems to me that Bush brought that upon himself. The Dems proved that they were willing to work with him until he proved himself untrustworthy.
Once the Dems got burned, they started resisting Bush's measures. This seems like caution to me, not partisanness. When Bush encountered this resistance, he would say that the Dems were being too partisan and that they wouldn't compromise. However, his idea of compromise frequently meant something along the lines of "doing things completely the way Bush wants". For example, when the federal judges were being appointed, Dems didn't want to confirm a couple of the judges. "Dems won't compromise." was Bush's complaint. But Bush was getting the 17(?) out of 19 of his judges. Compromise, I suppose, would have meant getting 19 out of 19.
On the national front, it just looks like Bush cannot deal with this level of opposition (which does not look markedly more fierce than in other administrations).
Onto the international front...
If even half of the pro-Bush pro-war crowd's rationales for going to war were correct, then it should have been a piece of cake for Bush to convince the entire world that we should invade Iraq. As, I have said, I think there was (at least) one compelling reason to invade Iraq. (Though the timing and manner of invasion would almost certainly been different if my rationale had been primary.) That Bush was unable to convince so much of the world that this was a wise course of action shows that he is not terribly persuasive. And make no mistake about it, persuasiveness is a key attribute of a good leader; if not, few will follow. And a leader with no followers is by definition not a leader.
Now the standard response to this is that the leaders of other nations are horribly corrupt and that's why they wouldn't follow Bush. I have several responses to this.
1) When in history has this not been the case? Despite the corruption of other leaders, good leaders are still able to get people on board.
2) The "traditional allies" who did not support the war have as much to lose in the GWOT as we do. They share much of our freedoms and values and have similar economic interests. As such, our arguments should have been particularly persuasive to them. That Bush was unable to persuade them points to either A) A weakness in rationale, or B) Poor leadership skills. Take your pick.
3) The complaint that the leaders of other nations are corrupt does little to explain why the citizenry of those nations were overwhelmingly against the invasion of Iraq. The citizens weren't all corrupt too, were they? If Bush had been a good leader blocked by corrupt leaders, then the citizens of those nations would have rallied around Bush despite their leaders. This did not happen.
For these three reasons, I do not think that it was the case that Bush was a good leader but he was blocked by corrupt leaders of other nations. There may have been corrupt leaders of other nations, but I don't think that Bush was a good leader. Armed with all of the leverage that the POTUS has and armed with presumably good rationales, Bush was still unable to get the world to follow him. Conclusion: he is not ready for diplomacy and leadership at this level.