The best way to kill anything is do so from within. Many herbicides like Round Up work systemically, meaning it’s taken up by the foliage and then transported to the roots where the herbicide does its work.
Cancer is another example of killing from within. Quite often the infection starts with a single virus or cell somewhere in the body. That infected cell then replicates and replicates and continues to grow. Depending on the type of cancer, the cancer is spread to other areas of the body where it grows and further destroys the host. Eventually, the spread of the cancer is so extensive that it kills the host.
The communist regime that controlled Russia for 90 years fell due to internal factors more than anything external. Today in America, we are seeing how the removal of God has led to the rise of godless liberalism and consequently is killing the America that we knew.
Many Islamic nations have vowed to destroy Israel and the United States as well as Judaism and Christianity. Muslims are already moving into America by the hundreds and thousands and already taking over entire communities like Dearborn, Michigan.