Republicans never tried to "sow doubt" about the legitimacy of Obama's presidency. We gave Obama a chance to prove he would be a President for everyone. No one heard the term "not my President" until the American voter, in their infinite wisdom, had the temerity to elect Donald Trump and deny Hillary the coronation she, the media, most celebrities, and academia thought she was owed.
Obama squandered that goodwill with his "elections have consequences" comment to Senator McCain, his weaponization of the IRS against his political enemies, his rejection of any substantial Republican input in remaking one-sixth of the US economy through the (Un)Affordable Care Act . There was also his immoral (and probably illegal) walking of guns to the Mexican drug cartels without the knowledge of or permission of the sovereign country of Mexico all for the purpose of claiming gun violence in Mexico was a result of American gun culture. The ultimate goal was to use that narrative to support anti-Second Amendment legislation. Obama's ambivalence to the murders and killings his policies caused in Mexico as well as the killing of a US Border Patrol Agent and a US Drug Enforcement Agency agent definitely angered Republicans.
The fact that Obama's DOJ obliterated the rule of law and overtly politicized the department played a factor in Republican's using their political power to thwart or stymie Obama initiatives.
Don't believe it? Director of National Intelligence, James Clapper, lied to Congress. No charges. CIA Director John Brennan authorized spying on Congress. No charges. No one was charged for the debacle which was Operation Fast and Furious noted above. Whoops, the whistleblowers who exposed the criminality were targeted and sanctioned with demotions and "go-nowhere" positions. That's just one example of Obama's vindictiveness.
The most egregious example of Obama's politicized DOJ was the failure to indict (let alone failure to sanction) Hillary's crimes associated with the homebrew email system she set up to thwart Freedom of Information Act requests and to stymie congressional investigations. She allowed to pass over her unsecure server information classified at the highest levels. She gave access to that information to people who had no need or clearance to know. FBI Director Comey's press conference on the FBI's "investigation" of Hillary's crimes was laughable. He laid out point by point Hillary's guilt and then excused that guilt by claiming there was no intent. Anyone who has held a security clearance in the government knows and acknowledges with a signature that "intent" is not a requirement when it comes to violating the statute. Regardless, Comey's assertion that there was no intent is laughable on its face. Information cannot move from the most classified systems (the Joint Worldwide Intelligence Communications System – JWICS) to the non-classified Internet Protocol Routed Network (NIPRnet) where Hillary's homebrew server lived without specifically INTENDING to do so. Transfer of that information would necessarily involve writing it down and removing it from the Sensitive Compartmented Information Facility (SCIF) where the JWICs computer would be located. They could've also taken a picture with their cell phones. Except that in itself would violate regulations associated with a SCIF.
Of special interest will be when the damage assessment report which should have been done when Hillary's crimes were revealed finally is available to the public. The highly classified Special Access Program information which Hillary systematically and repeatedly exposed for exploitation by our enemies involve intelligence sources and methods. In other words, it revealed the identity of people spying for the US government in other countries. It is not beyond the bounds of possibility that those spies were potentially arrested, tortured, and put to death because of Hillary's transgressions. Obama's DOJ ensured that neither Hillary nor her minions faced any legal jeopardy or even sanction for their crimes.
Nothing that has occurred in the past four years has made people feel like there was a two-tiered justice system than that failure to sanction in any way (let alone indict) Hillary Clinton and her staff.
The investigation of Hillary's crimes led her to concoct the Russian Collusion Delusion as a means to distract from her revealing of information crimes and, ultimately, encumber the Trump Administration after her humiliating defeat. The associated spying on a rival parties political campaign and in later administration was an unprecedented betrayal of American norms and values by Obama.
I don't see how you can claim Trump Supporters did something worse during the Obama Administration.
Leftists claim that President Trump is resisting the peaceful transfer of power but give Obama a pass for his contribution to stymieing the incoming administration of a rival political party.
It's just another example of how leftists crave power and will do anything to get it.
It's surprising to read someone with your beliefs acknowledge that birtherism originated with Hillary.
Finally, the world didn't begin in January 2009. Rival political parties have been resisting the other's priorities since George Washington left the Presidency.