Obama gave a priceless gift to the GOP: immunity from prosecution and accountability for war crimes, torture, and other criminality. Still, many Democrats treat him as a hero.
In 2008, it appeared that the GOP was destined for many years of repudiation. They’d proven themselves corrupt, incompetent, and imperialistic.
Obama had a chance to reorient America to a new paradigm of Democratic progressivism. Instead, he hid Bush-era criminality from the populace; surrounded himself with Bush holdovers and Wall Street cronies; prosecuted the whistle blowers; and governed as a centrist. As a result, in 2010 and 2014 the GOP roared back to life. Americans were confused about who was to blame for the mess we’re in.
There are those who would say that impeachment of Bush, Cheney and others would have been too divisive and would have led to a backlash against Democrats similar to what happened in 1999 when Republicans impeached Bill Clinton. The analogy doesn’t hold. Clinton was impeached for (lying about) sex. Bush and Cheney could have been impeached for torture, deception about the grounds for invading Iraq, and other crimes. See Kucinich Introduces 35 Articles of Impeachment.