Complex sentence: Trump's idea to build a wall is founded on the idea that a barrier will keep the "bad drugs" away but he fails to acknowledge that drugs can reach the homeland by other means (via drones, tunnels, airports, etc).
Split into simpler sentences: Trump's idea to build a wall is founded on the idea that a barrier will keep the "bad drugs" away. Trump does not acknowledge that drugs can reach the homeland by other means (via drones, tunnels, airports, etc).