What it is, is a reaffirmation of the American democratic system.
If the president wants extraordinary war powers — such as trying suspected terrorists before military commissions — he has to receive that authority from Congress.
The same goes for warrantless wiretaps.
In the current political client, Bush will likely get whatever he wants.
But the president doesn't have those powers just because he says he does.
For Congress or the Supreme Court to check the president's authority is not tantamount to what Mark Levin called "conferring rights and privileges on terrorists."
It is America, at its best.
The money quote is from Associate Justice Stephen Breyer:
"Where, as here, no emergency prevents consultation with Congress, judicial insistence upon that consultation does not weaken our Nation's ability to deal with danger. To the contrary, that insistence strengthens the Nation's ability to determine — through democratic means — how best to do so," Breyer wrote in a concuring opinion.
"The Constitution places its faith in those democratic means. ... Our Court today simply does the same."