Ross Douthat carefully reviews Hayward's Reagan in today's NYTimes.  It's suggestive, and even sometimes critical tone, is worth noting if for no other reason than to compare it to liberal criticism of Arthur Schlesinger's partisan history of FDR: There wasn't much.  The last two paragraphs are good and elegant:

"Since 'The Age of Reagan' will probably find more readers among conservatives than liberals, this is the message they ought to take to heart -- that being like Reagan can mean more than simply checking off a list of ideological boxes, or delivering a really impressive speech. It can mean marrying principle to practicality, tolerating fractiousness within one's own coalition and dealing with the political landscape as it actually exists, rather than as you would prefer it to be. (And in Hayward's account of the flailing Reagan-era Democratic Party, conservatives can find an object lesson in what happens if you don't.)

There is also a message here for all partisans and all seasons -- for contemporary liberals as well as Reagan nostalgists, and for anyone who's invested himself in the redemptive power of politics. Reconsidering his hero inspires Hayward to meditate on leadership, on greatness and on the possibility of world-historical change. Channeling William F. Buckley, he ponders 'the limitations of politics,' the fact that "the most powerful man in the world is not powerful enough to do everything that needs to be done." From his lips, one hopes, to Barack Obama's ear."