The doctrine of free trade only prevailed in so far as it could be restated in terms which had a direct relevance to the existing position of England and existing conditions of international trade. And it was directly challenged by the representatives of Mr Chamberlain's school of Imperialist thought (see CHAMBERLAIN, JOSEPH). It thus became the work of economic science ruthlessly to analyse the existing situation, explain the issues involved in the commercial policy of different countries, and point out the alternative methods of dealing with present difficulties, with their probable results. Commerce and finance. The commercial policy of a state is merely the reflex of its system of public finance (see e.g. ENGLISH FINANCE). The absence of conviction in regard to British commercial policy naturally had its counterpart in the attitude of many men to the financial system of the country. The eulogies showered upon it in the past were no longer considered adequate. The great increase in recent years in British military and naval expenditure, made necessary by the exceptional demands of a state of war and the great development of foreign powers, was partly responsible for the new difficulties; partly it was due to the great extension of the functions of the state during the latter part of the 19th century. The former causes may be considered partly permanent, partly temporary; but those of a permanent character are likely to increase in force, and those of a temporary character will leave a deposit in the shape of an addition to the normal expenditure of the central government. The extension of government functions appeared much more likely to continue than to be checked. Normal expenditure might therefore be calculated to rise rather than fall. In spite of the vast increase in national wealth, it was found a matter of increasing difficulty to meet a comparatively slight strain without recourse to measures of a highly controversial character; and the search for new sources of revenue (as in 1909) at once raised, in an acute form, questions of national commercial policy and the relations between the United Kingdom and the colonies.