Megan McArdle lived in New York her whole life and I lived there for three months, but she's basically wrong about the successes of Michael Bloomberg and Rudy Giuliani.
For most offices, like city council, the Democratic primaries decide the election. That means that there are a lot of extremely powerful interest groups with very powerful electoral machines invested in the primaries. And they are far to the left of both America, and most of New York, which is why City Council meetings tend to sound like the forlorn remnants of a Socialist Worker's Reading Group.
These groups tend to nominate mayoral candidates who are a) fairly far to the left and b) extremely noticeably in hoc to many small interest groups who are not popular with most of the voters. However, a mayoral race is high profile enough that all the people who normally just reflexively vote Democratic will actually know something about the candidate. Like, for example, his name. And what makes the candidate popular with the interest groups almost definitionally makes them unpopular with the broad electorate.
The Republicans, meanwhile, nominate socially moderate, and somewhat fiscally conservative candidates who resonate with the majority of New Yorkers who are not members of a government union or activist group. Hence, Rudy and Mike.
This was true in 1989-1997, the three elections that featured Giuliani as a candidate. But coming up to the 2001 election it stopped being true. The Democratic Party had taken its lumps and ceded that Giuliani had been basically right about crime, about Broken Windows, about some aspects of the welfare state. Mark Green, the liberal Democratic Public Advocate who'd engaged in some epic Beowulf-Grendel clashes with Rudy, won the endorsement of Bill Bratton, Rudy's (estranged) first police commissioner. As David Plotz summed up in a 2001 Green profile:
Green is more practical on policy questions than Republicans will concede. Like most New Yorkers, he has come to realize the hopelessness of the free-spending, chaotic urban liberalism of a generation ago. Giuliani has turned even Democrats who loathe him into imitators… Green now favors welfare reform. He would abolish parole. And he has challenged the teacher's union, the most powerful interest group in New York Democratic politics. Green wants to hold teachers to higher standards, make it easier to fire incompetent teachers, and give principals more power to move teachers.
Yes, Green nearly blew the primary election and gave it to Fernando Ferrer, an absolute special interest candidate and a puppet of Al Sharpton. He still had a 40-point lead over Michael Bloomberg and the numbers didn't really move until 9/11. That started a huge swing to Bloomberg which Green aided by freaking out and saying he would have done as good a job on 9/11 as Rudy. (This seems less offensive six years on.) Giuliani endorsed Bloomberg and his post-9/11 Midas touch gave him the election, narrowly.
Obviously McArdle (and a few million other people) lived through this, but so soon after Karl Rove's adieu it seems worthwhile to point it out. The GOP's lock on Gracie Mansion has less to do with New York's one-party interest group-driven politics than the political serendipity of 9/11, just like Bush's 2002 and 2004 election wins obviously owed more to his "bullhorn moment" and al Qaeda fears than Rove's Shaolin realignment-fu.
UPDATE: McArdle responds:
Mmmm . . . maybe. I concede that 9/11 had a big impact, but it's more complicated than that. The Democratic primary was supposed to be held on September 11th; one of my friends saw the towers hit as she came out of the voting booth. The primary ended up being held on September 25th, and Green's ultimate win may plausibly be attributed to a rightward shift post-9/11. The nomination in 2005 went to… Fernando Ferrer.
Most of this sounds right, although one reason Green nearly lost the nomination to Ferrer was his September 26th endorsement of Giuliani's plan to extend his term of office. Green was set to crush Ferrer in the runoff election. Remember, the two candidates eliminated in the first round of voting were bland New Democrat Alan Hevesi and Queens conservative Democrat Peter Vallone. Their voters weren't about to jump to Ferrer.
Anyway, I'm only dredging all of this up because it's tough to isolate the effect 9/11 had on politics. In retrospect Karl Rove's brilliance and John Kerry's bumbling and the pushes to give the GOP an advantage on education (NCLB) and health care (Medicard Part D) issues look, in retrospect, to have mattered less than the 9/11 effect.