That special prosecutor is Robert Mueller -- who served for 12 years as the nation's 6 FBI Director. He was confirmed for that job on a 94 - 0 Senate vote, and served under both President Bush and President Obama. He's not a politician, but a career law enforcement guy -- having also served as U.S. Deputy Attorney General, U.S. Attorney (in both California and Massachusetts), and U.S. Assistant Attorney General for the Criminal Division.
This will probably delay the results of the investigation, but that's not all bad. At least we'll know that a real investigation was done (instead of a GOP-led congressional whitewash). And the investigation will probably be going strong as the 2018 election approaches.
I'm sure we'll hear the Republicans whine that everyone needs to shut up now and let the investigation proceed. That will not happen. It didn't happen when Nixon was being investigated, and it won't happen now. The media will continue to report on every new detail, and that's also a good thing -- since the people have the right to know what Trump and his aides did.