I don't know whether Russia interfered with the election in any substantive way. I don't know whether anyone in the Trump organization colluded (if Russia did). I don't know why Russia might have preferred Trump to win (although I can infer). I don't know what might have happened had Russia not interfered (if they did) or whether the outcome would have been different.
I do know that information was released that likely damaged Hillary Clinton's campaign both by the FBI and via other avenues. I know that information was not released on the Trump campaign including from the CIA who believed that Russia was helping out the Trump campaign...
Sooooo... an investigation seems critical. If a foreign government is interfering in our elections, we need to know and it needs to be addressed. As one former CIA chief has said, this is "the political equivalent of 9/11."
To those Republicans who investigated Bengazi 7 times, each time hoping for a different result but each time claiming that the American people deserve to know and who are now saying that an investigation into possible interference by Russia into the presidential election is not necessary... once again, you are showing that you have no real interest in the truth or in justice, but only in power. Your hypocrisy is astounding and blatantly obvious.