No, Mr. President, we don't.
Mr. Trump spoke these words at the annual "Faith and Freedom Coalition" gathering of Christians who call themselves evangelical (or is it evangelicals who call themselves Christian?). It was red meat thrown to the lions (sorry for the upturned metaphor, couldn't resist). Both the President and this group of evangelicals love to be under siege. It seems to be from whence cometh their reason for being.
More than once Mr. Trump has confused evangelicals with all Christians (playing into the confusion many evangelicals have always had, to wit, the Roman Catholic Church is a cult, mainstream Protestant Christian denominations have been overtaken by godless liberals, etc.
Christianity is not under siege in America. Disagreement on ethical issues doth not a siege make, especially considering the disagreement is among the various people who call themselves Christian. True, some public laws are difficult for some Christians to accept and to follow. This has always been the case. There is nothing new here. Christians have been issuing divorce decrees for reasons not allowed by a literal reading of Jesus' teaching for as long as such divorces have been allowed (and baking wedding cakes for second marriages which, again in a literal reading, Jesus condemns as committing adultery, one of the ten big sins.
Christian numbers are shrinking, and that is cause for alarm for many, but we who call ourselves Christian have no one to blame but ourselves for this crisis. People are not attracted to institutions who are involved in constant public infighting, spend ungodly sums of money keeping their pretty buildings standing, and are unwilling to risk everything for the sake of following the one they rather cheaply call "Lord." Yes, some cultural things have not helped, such as youth sports on Sundays and the end of the Blue Laws. I believe we could have easily dealt with these new realities if we were entirely focused on the good news of the gospel, setting people free to live with all the imagination, creativity and compassion that God intends.
The road marked "we are under siege" is a road to nowhere. It is certainly not the road to Emmaus or Galilee or Jerusalem.