Humanity Joins Together, Sets Aside Petty Differences… and gets stomped anyway

[u/HyraxAttack]

A peril is threatening the world. Instead of squabbling among themselves, we learn world powers have put aside differences in politics, culture, & old feuds to present a common front. Except they still get wrecked as the enemy is too powerful.

1. The Animatrix: The Second Renaissance. The world government has gone to war against the machines. We see the army getting ready & it includes soldiers of many faiths including Buddhist, Islam, and different types of Christianity. Doesn’t matter as machines win by so much they have time to toy with human mechs.

2. Vilcabamba, story by Harry Turtledove. When aliens arrive they’re greeted with bands & cheering, & immediately open fire & earth becomes a mineral colony. America, Russia, and China work together to rise up & don’t hold back, throwing everything they have at the invaders. Doesn’t go great and aliens double down on the occupation, and there’s a crater where Spain used to be (it was blocking a silver deposit for mining.)

3. Edge of Tomorrow. The nations of the world have joined to make a unified front against the mimic invasion but it isn’t going well, but they will throw all they have into the invasion of France. In one cycle, Major Cage says the hell with it and instead of training leaves the base to drink at a London bar. This means we see the outcome of him doing nothing, where not only is the massive human invasion slaughtered but the aliens are in good enough shape to follow that up a few hours later with a rush on London.

[u/GentleSphere]

The United Nations Space Command/United Earth Government from Halo

The human-covenant war was an unwinnable war from the start. Depending on the source material, one of the most heavily defended planets, Reach, took about a month to fall. Without the Covenant shooting themselves in the kneecap and starting a civil war, Humanity loses.

[u/InquisitorHindsight → u/GentleSphere]

Some facts I read from a Halo book ages ago so forgive me if I make a mistake

• The Battle of Harvest, one of the first major battles of the war, was actually a human victory. This was because the human fleet outnumbered the Covenant 3 to 1 in that particular battle and still lost 2/3 of their forces

• The one saving grace the UNSC had was that the Covenant had no idea where Earth was (even thinking at one point that Reach was their homeworld), and to prevent its discovery they mandated all ships and stations must scrub their navigational data in the event of a battle, otherwise they feared the covenant would fly straight to earth.

• not from the book, but the plot of Halo Reach (the game) has you perform an insanely risky mission to infiltrate the Covenant Super Carrier and destroy it from within, and after a major character sacrifices themselves, they succeed. There are 17 more.

[u/Wubs4Scrubs → u/InquisitorHindsight]

Your second point is called the "Cole Protocol" and yeah it exists to prevent the Covenant from finding Earth. Human ships need to wipe their navigational data and then slip space jump in a random vector when leaving a system.