We thought that by contracting a joint engagement we might
     remove the difficulty and prevent Belgium from being
     sacrificed.

The policy of the Government continued, however, to be criticised, mainly on the ground that the Treaty of 1839 amply covered the case.  On Aug. 10 Gladstone defended his policy in the House of Commons in a speech pitched on a high moral plane, in which he dilated upon Belgium’s historic past and splendid present and on Great Britain’s duty to this little nation irrespective of all questions of its own self-interest.  With genuine fervor, he exclaimed: 

If, in order to satisfy a greedy appetite for aggrandisement, coming whence it may, Belgium were absorbed, the day that witnessed that absorption would hear the knell of public right and public law in Europe....  We have an interest in the independence of Belgium which is wider than that which we may have in the literal operation of the guarantee.  It is found in answer to the question whether under the circumstance of the case this country, endowed as it is with influence and power, would quietly stand by and witness the perpetration of the direst crime that ever stained the pages of history, and thus become participators in the sin.

What Gladstone Had in Mind.

What Gladstone had in mind was the scheme of 1866-7, by which France was to absorb Belgium, with Prussia’s consent and aid.  He distinctly stated that the Treaties of 1870 were devised to meet the new state of affairs disclosed by the publication of this incomplete treaty.  It was in order to prevent the revival of such a conspiracy that Gladstone made separate and identical treaties in 1870 with France and Prussia.  They were a practical device to secure an effectual enforcement of the Treaty of 1839 under unforeseen and difficult circumstances.  The agreement of 1870 was, as Gladstone said, a cumulative treaty added to that of 1839, and the latter treaty

     loses nothing of its force, even during the existence of this
     present treaty.

During the course of this speech defending the Government’s action against those critics who claimed that the Treaty of 1839 adequately met the situation, Gladstone made some general remarks about the extent of the obligation incurred by the signatories to the Treaty of 1839: 

It is not necessary, nor would time permit me, to enter into the complicated question of the nature of the obligations of that treaty, but I am not able to subscribe to the doctrine of those who have held in this House what plainly amounts to an assertion that the simple fact of the existence of a guarantee is binding on every party to it, irrespectively altogether of the particular position in which it may find itself at the time when the occasion for acting on the guarantee arises.

It is, of course, impossible to state precisely what were those unuttered thoughts that passed through Gladstone’s mind as he spoke these characteristically cautious words, but what in general they were can be satisfactorily gleaned from a letter that he had written six days before this to John Bright: