Royal - I mean, Presidential - Veto

President Bush has just veto'd his first piece of Congressional legislation, about public [ie taxpayer] funding for stem cell research. As you would not have gathered from the shrill BBC coverage, it is remarkable that George Bush has taken this long to wield the veto, which is accepted in the USA as a political tool in a way in which the (withholding of the) Royal Assent to legislation is not in the UK.

To be fair to the Beeb, they attempt a Q&A page on the stem cell issue elsewhere, but actual information about the US Veto requires following a link to their Clerk's Office for some statistics.

Of course, this new rarity of vetos requires interpretation. Does it mean that Congress is strong and the President weak ? Or vice versa, so that they don't produce veto-able stuff ? Or is it just that they both agree much of the time ?