Difficulties such as were encountered by Nelson withstood Great Britain's advance throughout this region. While neither blind nor indifferent to the advantages conferred by actual possession, through which she had profited elsewhere abundantly, the prior and long-established occupation by Spain prevented her obtaining by such means the control she ardently coveted, and in great measure really exercised. The ascendency which made her, and still makes her, the dominant factor in the political system of the West Indies and the Isthmus resulted from her sea power, understood in its broadest sense. She was the great trader, source of supplies, and medium of intercourse between the various colonies themselves, and from them to the outer world; while the capital and shipping employed in this traffic were protected by a powerful navy, which, except on very rare occasions, was fully competent to its work. Thus, while unable to utilize and direct the resources of the countries, as she could have done had they been her own property, she secured the fruitful use and reaped the profit of such commercial transactions as were possible under the inert and narrow rule of the Spaniards. The fact is instructive, for the conditions to-day are substantially the same as those of a century ago. Possession still vests in states and races which have not attained yet the faculty of developing by themselves the advantages conferred by nature; and control will abide still with those whose ships, whose capital, whose traders support the industrial system of the region, provided these are backed by a naval force adequate to the demands of the military situation, rightly understood. To any foreign state, control at the Central American Isthmus means naval control, naval predominance, to which tenure of the land is at best but a convenient incident.