[quote=@Ever Faithful]
I wonder how President Superman and Captain America would meet. Since Steve Rogers grew up in 1930s and 40s America, it's quite the eye opener 
[/quote]

Fate grew up in 1910s England. I actually plan on his, shall we say, [i]problematic[/i] past being a part of his character. He was literally one of the Black-and-Tans before he got his powers.

[quote=@Sep]
<Snipped quote by Dead Cruiser>

Register with the [i]United Nations[/i]. S.H.I.E.L.D is a global peacekeeping taskforce. Technically speaking President Supes isn't Caps boss.

JL is just [@Master Bruce] paying people to be his friends.
[/quote]

Maybe we need a fictional history for each org.

My idea is like... Avengers were formed as an unofficial alliance of Allied superheroes in WWII. Later grandfathered into SHIELD following the formation of the United Nations.

The Justice League was originally the Justice Society of America, and was also formed after WWII by the likes of Alan Scott, Jay Garrick, Carter Hall, etc. Membership changes and bankrolling from Wayne changed it from basically a drinking club for veteran superheroes into the global defense alliance it is today as the Justice League.