If they had the ideology of ethnically cleansing / enslaving all other religions in north america (aka literal nazis) yeah lets go. Worldwsr 2 was about that! Dont have to be successful to be evil!
Palestinians crossed a border to murder and kidnap people. What would the USA do if 5.000 Mexicans, many of them on an official mission by the Mexican government, would come to the US and murder a thousand US citizen and kidnap 250 of them?