If a president of the world power is a trader and in support of bitcoin, It will affect bitcoin positively, countries,people will now start to legalize bitcoin on their own.
If you were in any way subtly referring to the new man in saddle at the US Whitehouse lending his support to Bitcoin to make it grow, then you've missed the point. Bitcoin is community driven as a decentralized asset.
Not the main point of bitcoin as a decentralized cryptocurrency, but any support from a President still a plus point for bitcoin community to encourage more people to at least learn about the advantage of bitcoin.
No single person can manipulate it. Otherwise, Bitcoin wouldn't be as relatively stable as it is today.
bitcoin isn't a relatively stable coin, the price could change thousand of dollars in matter of hours or days, not to mention how much it fluctuate in months.
Because it can be manipulated by whoever have huge capital to do so, or by people who hold the title as bitcoin whale, they can dump it.
Bitcoin is an object of manipulation, it isn't stable.