How do you defend against cruise missile and nuclear attacks?

[Sydero]

Is it possible to defend against nuclear and missile attacks or is there nothing that can be done? Do fighter aircrafts help? I haven't had any experience with defending against or using these weapons.

[SpacingOutMan]

Missile Defense improvement.

Spies, Cruise Missiles, and Bombing Runs can destroy cruise missiles/nukes.

[Syzygy]

you can take out his stockpiled CMs and Nukes with successfull SpyingOperations. Also you can buy MissileDefenseSystems to lower the damage of incoming CMs.

Against a nuclear armed opponent, only bill-locking is effective. Make sure to throw him into anarchy (preferable nuclear anarchy) as soon as possible. This will greatly reduce his tax income and he must use stockpiled cash to pay his daily bills. Also you can destroy or loot his cash with successfull ground battles and spying operations. Once he is out of cash and has 3days unpaid bills, he cannot launch any attacks (including nukes) against you. If your enemy is clever and has saved up large amounts of cash, its nearly impossible to bill-lock him in the first war (7days), so unfortunately you will eat 6 nukes before the war expires. You cannot prevent the infra-damage, but you can stop collecting tax until the anarchy wears off. The you collect some dozen millions at once and rebuild your lost infra.