If you're wondering why we can't just accelerate at 1G for half the journey there, then with a brief but fun interlude at 0G, flip around and decelerate at 1G t

If you're wondering why we can't just accelerate at 1G for half the journey there, then with a brief but fun interlude at 0G, flip around and decelerate at 1G the rest of the way: today's rockets would deplete their fuel too quickly (minutes or maybe hours at best). I wonder if a hypothetical, high-Isp fusion rocket could manage it (incidentally the journey would only take a couple days or so).