Russia is a country which takes pride in it's history of espionage and influence. It is within their best interests to meddle in American politics to gain the best deal for them, especially as they have so many sanctions against them from the UN. Every powerful government needs to be wary of them.
Unfortunately this world has become a very corrupt place. I think that any issue of corruption should be investigated by someone outside the governing body. Those within it have too much to lose. Independent investigation would make it far more likely that the truth would be revealed to the general public.
it is waste of time. McCain, Schumer and other senators say a select committee is needed to "reconcile contradictory information" and give the issue needed focus. Trump won in part because he was able to connect with rural voters in states such as Michigan, Pennsylvania and Wisconsin that had previously voted for Democrats.
The people who think that Russia hacked the United States election are just unhappy with the election result. They are just looking for someone to blame. Even Bill Clinton wants to blame the Russians for the fact that people thought Trump was more qualified to be President. There is nothing to investigate.