The most palpable violations of constitutional duty which have yet been committed consist in the acts of different State legislatures to defeat the execution of the fugitive-slave law. It ought to be remembered, however, that for these acts neither Congress nor any President can justly be held responsible. Having been passed in violation of the Federal Constitution, they are therefore null and void. All the courts, both State and national, before whom the question has arisen have from the beginning declared the fugitive-slave law to be constitutional. The single exception is that of a State court in Wisconsin, and this has not only been reversed by the proper appellate tribunal, but has met with such universal reprobation that there can be no danger from it as a precedent. The validity of this law has been established over and over again by the Supreme Court of the United States with perfect unanimity. It is rounded upon an express provision of the Constitution, requiring that fugitive slaves who escape from service in one State to another shall be "delivered up" to their masters. Without this provision it is a well-known historical fact that the Constitution itself could never have been adopted by the Convention. In one form or other, under the acts of 1793 and 1850, both being substantially the same, the fugitive-slave law has been the law of the land from the days of Washington until the present moment. Here, then, a clear case is presented in which it will be the duty of the next President, as it has been my own, to act with vigor in executing this supreme law against the conflicting enactments of State legislatures. Should he fail in the performance of this high duty, he will then have manifested a disregard of the Constitution and laws, to the great injury of the people of nearly one-half of the States of the Union. But are we to presume in advance that he will thus violate his duty? This would be at war with every principle of justice and of Christian charity. Let us wait for the overt act. The fugitive-slave law has been carried into execution in every contested case since the commencement of the present Administration, though Often, it is to be regretted, with great loss and inconvenience to the master and with considerable expense to the Government. Let us trust that the State legislatures will repeal their unconstitutional and obnoxious enactments. Unless this shall be done without unnecessary delay, it is impossible for any human power to save the Union.