That President Bush won the election is beyond argument. Did he win a mandate? As such things are normally talked of, the answer would be "yes." Yet, as
Andrew Busch reminds us, it is unfortunate that we talk in such terms. The mandate question reminds us that Woodrow Wilson and the progressives used this term first to argue that the president is given authority by the people because they elect him. Wilson and the other progressives were keen to go beyond the Constitution.
We should remind ourselves of our constitutional heritage: that the president’s authority resides in the Constitution, not in a plebiscite. Every presidential election should remind us of this massive fact. 
It is difficult to keep track of the commentary/articles loudly proclaiming the lack of mandate for the 43rd president in 2004. RCP points to the 130,000 vote margin in Ohio as evidence of the lack of mandate ...... further, they point out that only four elections since 1888 have been closer than 2004. What they conveniently fail to tell us is that only 88,000 votes kept Bush from winning Wisconsin, New Hampshire, Hawaii and Delaware for an additional 21 EVs or why they conveniently chose 1888 for their analysis ..... could it be because the elections of 1884 and 1880 were closer than 2004, or because the election of 1876 was by the same margin as 2004, or because Lincoln failed to get a majority in 1860 nor did Buchanan in 1856, or could it be because there have been 13 presidents that governed without a majority of the popular vote and Bush had a majority.
So hence forth, we will only say that Bush has been commissioned by the electorate ..... or authorized by the electorate ..... or ordered by the electorate ..... or instructed by the electorate ..... or given a promissory note from the electorate, to implement his policies. We shall never again use the inappropriate term mandate.