Harris, whose campaign says she has secured the Democratic nomination, led Trump 44% to 42% in the national poll, a difference within the 3-percentage-point margin of error.
National polls go beyond meaninglessness and into actual harm. The national popular vote does not elect the president, as we all should know too well. My vote in Illinois is worth far less than someone's vote in Wyoming. Your vote in California is worth far less than someone's vote in Alaska.
Unless a national poll weights responses based on state, and based on the electoral college results from states, it is completely misleading.