The Resistance (RES, colloquially known as smurfs) is one of the two factions in Ingress, represented blue within the game. Where the Enlightened are convinced the Shapers are trying to help humanity evolve, the Resistance believes Shapers are here for their own purposes and want to protect humanity from the Shaper influence.
The Resistance believes that the Shapers plan to stage a 'hostile takeover of the human mind' and aim to keep XM in lockdown to prevent this from occuring. They believe XM should be studied to hopefully be utilised to help evolve mankind on its own terms, preventing the Shapers from fulfilling any unknown ulterior motives they may have.
ADA is the ultimate culmination of Resistance ideology. As the most powerful supercomputer created and coded by human minds, ADAcomprises the software loaded in to Resistance scanners. When the Resistance captures a portal, a piece of ADA is uploaded, and the portal turns blue.
Due to the difference in perspective over the Shapers and their motives, and the appropriate utilisation of exotic matter, the Resistance and the Enlightened exist in a perpetual state of conflict on Earth.