Board Thread:Young Justice News/@comment-47881-20130128165351/@comment-4928331-20130318022319

Here's a fan rationalization. Let's list down the changes made by Impulse. He:

1. Saved Flash. No Flash, not enough kinetic energy to siphon off the chrysalis

2. Saved Blue in BEFORE THE DAWN, forcing the Reach to deploy their hidden Green Beetle. Blue was rebooted by Green, instead of Scientist after a detailed study. Or possible that Jaime dies and is replaced by someone.

3. Confirmed Justice League theory about on-mode Beetles, when he mouthed off to Blue about the apocalypse. As a result, the league accelerated their study on the scarab temple in the event that Blue goes rogue.

4. Helped cleanse Green in INTERVENTION, removing him from the equation permanently. If Blue were cleansed and Green was not,  Black would have been sent while Green takes potshots. The Bialyan Team would have died right there.

5. Helped the Flash siphon kinetic energy off the chrysalis.

Note that the Reach wanted to destroy the Earth, so they planted 21. Maybe in the original timeline, they only planted one or two -- enough to put the Earth's climate out of whack, but not enough to destroy it. And the Light would not have enough assets to fight them.