Commercial blockade, therefore, has an intimate relation with naval blockade in its open form. We adopt that form when we wish his fleet to put to sea, and commercial blockade is usually the most effective means we have of forcing upon him the movement we leave him free to attempt. By closing his commercial ports we exercise the highest power of injuring him which the command of the sea can give us. We choke the flow of his national activity afloat in the same way that military occupation of his territory chokes it ashore. He must, therefore, either tamely submit to the worst which a naval defeat can inflict upon him, or he must fight to release himself. He may see fit to choose the one course or the other, but in any case we can do no more by naval means alone to force our will upon him. In the long run a rigorous and uninterrupted blockade is almost sure to exhaust him before it exhausts us, but the end will be far and costly. As a rule, therefore, we have found that where we had a substantial predominance our enemy preferred to submit to commercial blockade in hope that by the chances of war or the development of fresh force he might later on be in a better position to come out into the open. That he should come out and stake the issue in battle was nearly always our wish, and it was obvious that too rigorous a naval blockade was not the way to achieve the desired end, or to reap the strategical result which we might expect from paralysing his commerce. Consequently where the desire for a decision at sea was not crossed by higher military considerations, as in the case of imminent invasion, or where we ourselves had an important expedition in hand, it was to our interest to incline the enemy's mind towards the bolder choice. The means was to tempt him with a prospect of success, either by leading him to believe the blockading force was smaller than it was, or by removing it to such a distance as would induce him to attempt to evade it, or both. A leading case of such an open blockade was Nelson's disposition of his fleet off Cadiz when he was seeking to bring Villeneuve to action in 1805. But merely to leave a port open does not fulfil the idea of open blockade, and in this case to opportunity and temptation Nelson added the pressure of a commercial blockade of the adjacent ports in hope of starving Villeneuve into the necessity of taking to the sea. Finally, in a general comparison of the two forms, we have to observe that close blockade is characteristically a method of securing local and temporary command. Its dominating purpose will usually be to prevent the enemy's fleet acting in a certain area and for a certain purpose. Whereas open blockade, in that it aims at the destruction of an enemy's naval force, is a definite step towards securing permanent command.