Grant demonstrated a fundamental fact of war and militarism. War is said to be diplomacy by force and coercion. If you are engaged in such an endeavor and do not fight tenaciously and viciously, many of your own men will be killed and resources will be squandered needlessly. A successful general is audacious, engages the enemy and is willing to accept losses to achieve goals. Of course Grant had huge resources, could afford strategic mistakes, incur huge losses have a few drinks, then get up and fight again. Eventually and inevitably he won. Whether you are Finland or the Confederacy, overwhelming numbers and determination almost always wins.
“War is politics by other means’’.- Clausewitz.