The foregoing discussion points to the conclusion that, while an extensive or exclusive reliance upon taxes is theoretically advisable, yet the practical aspects of the case nearly always make some use of loans desirable. The problem of the revenue administrators is to hit upon the proper combination in the use of these two sources. It will usually happen that greater reliance must be placed upon loans at the beginning of the emergency. Revenue systems are not usually in operation which will permit of sufficient expansion to meet the immediate demands. Public sentiment, likewise, may have to be developed before individuals are willing to endure the feeling of sacrifice. At the beginning, then, the extensive use of the borrowing power may be the proper solution. This does not mean that it should be the permanent policy. The authorities should at once begin to develop new taxes and to expand the old where it is possible. As time goes on, the habit of paying more taxes will be formed, and little opposition will be encountered. As public sentiment becomes more favorable, taxation can be pushed more rapidly, until it may be made the chief source of revenue.

If any policy for the proper procedure of officials were to be formulated it would be something like this: use taxes at the beginning as much as possible, but not to such an extent as to antagonize individuals or discourage industry; introduce taxes as rapidly as possible, so that as time goes on the majority, if not all, of the needed revenue shall come from this source. In the light of the underlying principles which have been discussed in the preceding pages, it will be instructive to review some of the methods which have been used in financing wars, to see how closely they have adhered to these principles, and to note the degree of success which was attained.