President Clinton was Impeached because, unlike Obama (who is just a subservient flak), Clinton resisted some of the big plans that the Elites had, and had the ability to think and reason independently.
The Elites did not like the fact that:
1. Clinton reversed the debt-generating Trickle-Down/Reagan Tax Code, which then made the Tax Code more progressive and led to balanced budgets, and even budget surpluses (for the first time in over 100 years). The great gap between the poor and the rich actually narrowed during the Clinton years as a result, and the middle-class prospered. That's not what the Elites want.
2. Clinton refused to be threatened by the right-wing into terminating Medicare, and even allowed Newt Gingrich to shut down the government rather than give in. Eventually it was Congress that gave in, and Clinton won the standoff. The Elites don't want a President that goes against their agenda that hard.
3. Clinton wanted to also use the budget surplus money to save Social Security for the next 100 years. We all know that the Fat Cats on Wall Street hate Social Security, and want it ended. Clinton's Impeachment derailed his "save social security first" negotiations with Congress, and nothing was accomplished.
4. Clinton did not agree to invading Iraq, as the Project For The New American Century Neocons wanted. Instead they would have to wait until their puppet George W. (and "President" Cheney) had the Office stolen for them to enact their Middle-East Madness Plan, and decades of War.
Clinton did however cooperate with the Elites on many other things, such as NAFTA, and also terminating the Glass-Steagall Act (which led to zero investment rules for the Big Banks -- creating the 2008 Wall-Street Corruption, and current Economic Meltdown & Depression over the last 6 years), and also the Telecommunications Act deregulation -- which led to the creation of FOX News (Murdoch Media Empire). So Clinton did a lot of bad stuff too.
But Clinton was only a 50-50 player for the Oligarchs ... not good enough for the ruling class ... so they tried to make an example out of him, and force him out of Office.
Bush and Obama are 100% players. So despite their egregious mass-murder, high crimes, numerous Constitutional violations, and unmistakable treason --- nobody will ever touch them.
Jeb Bush and Hillary (or Biden) will also be 100% players for the Elites.
So there will be no more Impeachments, because there are no candidates left who will ever stand up to the power, and the control by the richest 1%.
But if Ron Paul had been elected, efforts would've been made to Impeach him as well. But Rand Paul....not so much (as he will also not break too far from the GOP Leadership agenda, but they likely won't even take that chance by letting him get elected).