Why didn't the Muslim invasion start a generation earlier? According to Muslims, it was because they were afraid their people would be converted to Christianity in America, the Christian nation.
They are not afraid any more.
Only God can hold back something politically. But it is governed by the spiritual. When people followed and feared the Lord, He placed His hand of protection over the people, time and time again. But when they kept turning away from Him, God had enough and removed His hand of protection from them.
If American Christians think they can sit back and be comfortable in their churches and pass down the same kind of country to their children, they are completely deceived.
Think of your children. The Muslims promise, over and over again, "We will take your daughters and make them our wives. We will take your children and make them Muslims." And it is no idle threat. This is how Islam has spread since its founding.