Liberal historians have been ranking Presidents for years and of course there's always a heavy leftward skew to their evaluations. Republicans are inevitably ranked lower than they deserve to be while Democrats are sure to be portrayed in the kindest historical light. Here's a different take on the issue: A look at the worst Presidents of the last hundred years from a conservative perspective.
7) Herbert Hoover (R): Hoover didn't make the list because the Depression started on his watch. After all, it's not as if he created that problem. But, his protectionist Smoot-Hawley Tariff Act created a trade war at the worst possible time and helped lock the Depression in place.
6) Warren Harding (R): Harding was only in office for a couple of years before he died of a heart attack. The bright side to that silver lining for Harding was that much of the incredible corruption that was going on during his presidency wasn't revealed until after his death. The worst of these ignominious adventures was the "Teapot Dome scandal," which involved bribery and a new first in American politics -- a cabinet member, Albert Fall, being sent to jail.
5) Richard Nixon (R): Not only was "Tricky Dick" Nixon almost impeached over Watergate, he shook the American people's faith in our government. Given the chronic overreach of the federal government, some might say that's a good thing. But, you generally get what you expect and if the American people don't expect competency, honesty, and decency from our government, we're not likely to get it.
Nixon did improve relations with China. He also put America in a position where we could have won in Vietnam had the Democrats in Congress not cut off supplies and air support to our former allies and left them to be slaughtered. Still, Nixon did a lot of damage domestically. He created the out-of-control EPA and was primarily responsible for creating the federal government's Affirmative Action program, which codified discrimination against white Americans into the law. Additionally, he imposed wage and price controls that hurt the economy. That’s not much of a domestic legacy.
4) Jimmy Carter (D): Not only did Carter stand by and watch our ally, the Shah of Iran, get overthrown by fundamentalist crazies, he botched the Iranian hostage crisis that sprang from the overthrow in almost every way possible. It's also worth noting that the Soviets were inspired by Carter's naiveté to invade Afghanistan on his watch. In other words, both the war on terror and Iran's quest for nuclear weapons can be directly traced back to Jimmy Carter's presidency. To top off all of that incompetence, Carter gave away the Panama Canal.