The nation is holding its breath and nerving itself for the shock of war. There has been no announcement of it, and the Government is certainly determined not to begin it. But the signs and portents are all about us. Patience, indulgence and forbearance have been severely tried, and after submitting kindly to bravado, violence and plunder, without discovering any signs that such submission is mollifying the temper of the Southern people, it seems to be understood that the Government is seriously about to undertake the defence of such of its property as still remains in its hands. It is about to show to the world that it thinks the Constitution, the Union, the institutions of Republicanism, the liberties won at the Revolution, are worth fighting for. They are all in danger, and if they are not defended, they will be destroyed. How can a government that is true to its trust, do otherwise than defend them?

During the five weeks that have elapsed since President Lincoln went into office, he has been studying the condition of the government, and learning all the miserable work bequeathed to him by his predecessor. The time has been short, and the President has been much interrupted in it by the importunities of office-seekers. But there has been a great deal done; the utmost activity has existed in all the departments, confidential messengers have visited all important points and returned with their reports, and after all this, whatever policy may have been adopted, it has been with the best knowledge that can be obtained, and a full appreciation of duties, risks and responsibilities. While this unusual activity has prevailed, the secrets of the administration have been well kept, even its subordinate agents revealing nothing that might endanger the execution of the government designs. This prudence, although it baffles curiosity, inspires confidence, and the people respect an administration that keeps its own counsel, instead of revealing everything to the prying gossips of the New York press, who have, in former administrations, performed the office of spies in the service of the enemies of the country.

It is with no disposition to alarm, or to excite a sensation, that we refer to the probability that the Government may, in a few days, be compelled to resist with violence the attacks of the Secession forces. But the matter is one of common talk, and it is best for the people to accustom themselves to the idea of war; for it is a frightful one, especially when the war contemplated is one forced upon us by those who should be to us as brothers; who have lived under the same free government, and inherited, in common with ourselves, the glories of the revolution and the freedom that it secured. But if there is a war, it will be made by the South, and the Government, sustained by the people of the North, will simply act on the defensive.

Let us glance briefly at the events that seem now to be about to culminate in a war. The State of South Carolina is the author of them all. Disappointed because Mr. Lincoln was elected, she seized the unprotected government property in and about Charleston, and passed an ordinance of secession. No other State would have done this, but for her example. She sent her emissaries to tempt, taunt or bully other States to imitate her, and she succeeded with six of them, though in no case with the ascertained consent of the people. A Congress, composed of delegates from the seven States, not one of whom was elected by the people, met and organized a Government, adopting a Constitution in secret session. This Government and Constitution were never assented to by the people of the seven States, but they are made to supersede the Government and Constitution of the United States, which had been adopted in the most solemn manner, by the direct votes of the people, and to which the States owed allegiance and obedience, if ever allegiance and obedience were due anywhere. Under this new arrangement, which is so impudently named a Government of the people of the seven States, though they have never been allowed to vote on it, the Government of the United States, which can recognize no authority not derived from the people, is asked to surrender all its property throughout the States referred to and in the Gulf of Mexico, and abandon the Union, the Constitution and the laws that it is solemnly bound to observe and defend. The first demand is for Fort Sumter; the next will be for Fort Pickens; the next for the other Florida forts; the next for the City of Washington, with the Government buildings and the archives; and the next, as may naturally follow, will be the Government property in Pennsylvania and the other Free States. The principle that would justify the yielding to one demand would apply in like manner to all the others. If Forts Sumter and Pickens are abandoned without making the most strenuous efforts to preserve them, then the Government need make no efforts to assert its rights elsewhere. In fact the crisis we have reached is one in which it is to be ascertained whether we have a Government or not. If the solution of the question is to be found only in war, for which the Secessionists seem to be anxious, then, horrible as it may be, let us have it quickly and decidedly. The sooner it is begun, the sooner it will be over. We cannot much longer exist in the ruinous and humiliating suspense that has continued so long. The war will be the work of the Southern people. The Federal Government has done everything that could be done to conciliate them, and it can yield nothing more, unless it yields everything. If further concessions are made, the South will be encouraged to go on, and finally to demand even the abdication of the President who was fairly elected, and the installation of Jefferson Davis as the President of the whole country.

In the conjuncture that is upon us, the duty of all honest patriots is a plain one. The Government must be supported by the people. Not supported in any hasty and violent aggressions upon the South, but in every firm, dignified and constitutional endeavor to maintain its position and preserve its authority. There is, even after all the violence of the South, no bitter rage among the Northern people. But the first attack upon the officers of the Government employed in obeying its orders for defending its property, will be a signal for rallying to the support of the President and the Union. For Pennsylvania we are sure we can speak, and we say that she will make every sacrifice of men and money that may be required of her. She has not bullied, or blustered, or even armed herself, as most of the Southern States have done. But, though she may be taken at a disadvantage, she will yet prepare herself in time, if the Montgomery Government persists in its determination to open a war with the United States.