Why does Aldrich ignore important parts of our history?

Aldrich is concerned about putting politics into nice little chunks of critical and stable political time periods. Looking at the 90’s to see if it fits this frame of either stable of critical seems a bit of a folly. First off, it seems odd that Aldrich would consider the 60’s the closet critical period with the 70’s as stable. The 70’s had seen the impeachment proceedings off a president, as well as growing anti war movement that culminated in the passage of legislation that was supposed to restrict the war powers of the executive. Also during this decade we saw big social changes made: the APA (American Psychiatric Association) removed homosexuality from its list of mental disorders, the USSC legalized abortion in Roe V. Wade, and the Middle East started causing trouble (oil embargo, Iran Hostage Crisis). While these may not be directly be tied to party leadership, they do however change party platforms from then on. The 80’s isn’t without its share of political issues either: AIDS, rise of the Moral Majority, FOX News is started, and the Berlin Wall came down (talk about changing the political landscape). Of course all of that was supposed to be the “stable era”. Now the 90’s could be critical; however, other than the Republican takeover, there hasn’t been much change institutionally since the decade started. The impeachment of Clinton doesn’t count since the impeachment proceedings and resignation of Nixon didn’t. As for redistricting, it is nothing new, and while I don’t know as much as others in the class, I do think the new way of gerrymandering (the 51% margin of victory) isn’t probably that much different than other ways—at least in its ramifications (there will always be gerrymandering unless we write a computer program to split states into districts based on whatever). The political landscape is always changing, and there is never any stability. Are we supposed to believe that there are only six, maybe seven critical eras in our history. Aldrich doesn’t discuss the Civil War or Reconstruction (as mentioned in passing in class) surely a time period that split the nation in half and ended with an increase of power to the Federal government, as well as expanding the electorate to former male slaves should be worthy of the designation of “critical”. Secondly, he doesn’t mention the Progressive Era from the 1900’s to the 1920’s where three important Constitutional Amendments were passed, the income tax, direct election of Senators, and not to mention Women’s suffrage (talk about institutional change). Of course what about Teddy Roosevelt’s run with the (class favorite) Bull Moose party as a third party candidate during this period (big political ramifications). If the 90’s were critical, than I’m not convinced we’re living in stable times. We have a president who’s intent on absorbing the other two branches into the executive. A vice president who has become, arguably, one of the most powerful man in the country in an office that Constitutionally has no power. We have seen the passage of a law that has overturned centuries of common law (the disappearance of Habeas Corpus). Finally, we have parties using referendum as ways to influence elections. Either the 2000’s (why hasn’t anyone came up with a name for this decade yet?) are continuation of the 90’s critical era, or the start of a new one. I’m not convinced that America has any periods of stability, all periods are critical to its future.