What is the underlying difficulty the world/planet faces?
For myself, I think it’s over population. Organizations such as Planned Parenthood are very, very important.
What would I do with the power of a USA president?
Reduce it.
Imprison Trump?
Ok seriously.
If I were President/Prime Minister, my main mission would try to improve the quality of education especially with respect to critical thinking. Everything else can be solved if we start raising people who can think critically.
That’s a good one. Science and fact needs to be in the forefront of all education. Half of the USA seems to think that’s not important.
Ban Trump. Everything Trump.
This is not anything close to a Great Debate and as it is polling for opinions, it is moving to IMHO.
On alternate Thursdays, everyone wears their underwear on the outside.
Pretty much like R. Crumb, when he did a four-pager called “If I was King of the World” about 20 years back.
First, take away everybody’s guns, motorcycles, jet-skis, power tools, and other loud things.
Second, install a Secretary of Women’s Footwear.
Third, schedule a morning meeting with her every day.
Make healthcare universal and free. Cut the shit out of the military budget to fund this.
Enact prison reform.
Enact ACTUAL sanctions against regimes with massive human rights violations. Saudi Arabia, Qatar, etc…
Refuse to allow the US Soccer team to go to Qatar. Try and organize an alternate WC.
Pick a really good VP as I doubt I make to the second month of my first term.
Enough of the exploitation: get rid of the dumbass business model and bring in a standard Parliamentary democracy.
I hate to burst your bubble, but that is not even remotely within the power of the president to do.
…lock up John Mace.
I would veto every bill passed by Congress … making them play nice with each other to get their 2/3’s majority … yeah, that means shutting down non-essential government services … so sue me …
Close Guantanamo. Release all currently held detainees, and if nobody else accepted them, release them with green cards into the general population of the District of Columbia, which I don’t think anybody could legally obstruct. If any of them commits a crime then, they will be prosecuted the same as any other legal resident, so they would not be particular threat to anyone. I think there are now 61 of them, entering into their third presidential administration with no hope nor prospects of relief. Looking at 4 or 8 more years, but at least, they can look forward now to having lots of company.
Some future edition of “Thins I didn’t learn at school” will feature this as the most flagrant and unjustified abuse of human right in the history of the United States. By itself, it is reason enough to not stand up when the national anthem is played.
This, I think, is an executive action that can be accomplished with little more than a Tweet.
Yes, but it’d also mean shutting down essential government services.
And to answer the question, we really need to know what sort of Congress we’d have working with us.
This would be my serious goal.
On a much more lighter note, after resting from the inauguration and making the necessary legal arrangements with Bob Seger or whomever owns the rights to “Take Those Old Records Off the Shelves” I would recreate Tom Cruise’s lip-synching scene from Risky Business in the Oval Office and post it online.
Give the power away to someone who knew what they were doing.
A stab at election reform — remove the Straight Party Vote option and remove the little ®s and (D)s after all the names. And then hiding in a closet to avoid the screams from the career politicians on both sides.
Thanks. Now I’m going to be haunted all day by chants of “Lock him up! Lock him up!” 
Massive arms sales to US allies.
Raises taxes on the rich, install single-payer health care.
Toughest regulations on toxins and waste (for industry and pollution) America has ever seen.
Force universities to spend their endowments (OK, I don’t know if a POTUS can do that.)