Traditionally, the populace rallies around the president/government in times of crisis. Although this will be a manufactured crisis, it may have the same effect to bring the country together. In “normal” times, saying “support our troops no matter what” seems like excessive patriotism, but in crisis times, it is expected. Only a traitor or non-patriot would oppose their own country. Everyone knows that “God is with us,” so only a godless atheist would oppose what God commands.
Having a national crisis on hand will give Trump another excuse to be strongman to control election procedures. If that doesn’t work, he can always say “it was stolen,” so he always has an out.
This concept seems to be at work already. Look at the enthusiastic senate votes to wage war right now. Good thing for them that no senators are currently in the active armed forces, putting their life on the line.