I reccomend pointing out the enemy's hypocrisy (they accuse us of being bloodthirsty, but they themself support Hillary Clinton, who is STRONGLY pro-war, supported a coup in Honduras in which extremists murdered homosexuals, and while she doesn't want us to be armed, she wants to allow the sale of military equipment of governments of Israel, Saudi Arabia and supports arming ISIS).
Why not +mention this person and tell them the following; "Not only is Hillary the most warmongering candidate, but also, she wants to allow the sale of weapons and other military equipment with governments that have horrible humans rights records such as those of Israel and Saudi Arabia, and wants to support arming ISIS. Besides, there are places like the Czech republic that allows civilians to get military-style semi-automatic rifles without too many restrictions and Canada and New Zealand also have relatively loose firearm laws, but they're not too violent".
After you're done with that, hit them with a reshare of my ultimate argument, which can be found in my "Ultimate arguments" collection. I bet that they can't bust that.