Lincoln didn't violate the Constitution.
"Lincoln, with his usual incisiveness, put his finger on the debate that inevitably surrounds issues of civil liberties in wartime. If the country itself is in mortal danger, must we enforce every provision safeguarding individual liberties even though to do so will endanger the very government which is created by the Constitution? The question of whether only Congress may suspend it has never been authoritatively answered to this day, but the Lincoln administration proceeded to arrest and detain persons suspected of disloyal activities, including the mayor of Baltimore and the chief of police."
--Chief Justice William Rehenquist, November, 1999
"The President was not out to trample on the First Amendment. He was not out to crush his political opposition. He suspended the writ of Habeas Corpus in response to perceived military threats to the Union. After he, and later Congress, removed that Constitutional safeguard, the Lincoln Administration did not use its power selfishly or arbitrarily. It arrested only those people who actively supported the Confederate war machine--people like Merryman, who recruited troops to march south. And when people walked this fine line between political dissent and treason, as Vallandigham did, Lincoln tried to err on the side of free speech...
Midway through the war, Lincoln predicted that Habeas Corpus would quickly be re-instituted after the war was over. He could not bring himself to believe that Americans would allow the wartime suspension of Habeas Corpus to extend into peacetime, he said, "Any more than I am able to believe that a man could contract so strong an appetite for emetics during temporary illness as to persist in feeding upon them during the remainder of his healthful life." Lincoln died before he could see the writ of habeas corpus restored.
Lincoln asked:
"What constitutes the bulwark of our own liberty and independence? It is not our frowning battlements, our bristling sea coasts, the guns of our war steamers, or the strength of our gallant and disciplined army. These are not our reliance against a resumption of tyranny in our fair land. All of them may be turned against our liberties, without making us stronger or weaker for the struggle. Our reliance is in the love of liberty which God has planted in our bosoms. Our defense is in the preservation of the spirit which prizes liberty as the heritage of all men, in all lands, everywhere. Destroy this spirit, and you have planted the seeds of despotism around our doors. Familiarize yourselves with the chains of bondage, and you are preparing your own limbs to wear them. Accustomed to trample on the rights of those around you, you have lost the genius of your own independence, and become the fit subjects of the first cunning tyrant who rises."
So today, let us heed the wisdom of a man who led our nation to a "new birth of freedom." Let us always be, first and foremost, lovers of liberty."
-- Justice Sandra Day O'Connor, 11/19/96
Lovers of liberty -- like President Lincoln
Walt
Yes he did.
"The privileges and benefit of the writ of Habeas Corpus shall be enjoyed in this Government, in the most expeditious and ample manner; and shall not be suspended by the Legislature, except upon the most urgent and pressing occasions, and for a limited time not exceeding months." - Proposal of Charles Pickney on habeas corpus, Constitutional Convention of 1787, submitted to committee for consideration and later adopted in its current language as Article I, Section 9, Clause 2, pertaining to the legislature
"All legislative Powers herein granted shall be vested in a Congress of the United States...The Privilege of the Writ of Habeas Corpus shall not be suspended, unless when in Cases of Rebellion or Invasion the public Safety may require it." - United States Constitution, Article I
"In the same section it is provided, that "the privilege of the writ of habeas corpus shall not be suspended, unless when in cases of rebellion and invasion, the public safety may require it." This clause limits the power of the legislature to deprive a citizen of the right of habeas corpus, to particular cases viz. those of rebellion and invasion; the reason is plain, because in no other cases can this power be exercised for the general good." - Robert Yates, delegate to the Constitutional Convention, Anti-Federalist #9 "Brutus"
"The people by adopting the federal constitution, give congress general powers to institute a distinct and new judiciary, new courts, and to regulate all proceedings in them, under the eight limitations mentioned in a former letter; and the further one, that the benefits of the habeas corpus act shall be enjoyed by individuals." - Federal Farmer (believed to be Richard Henry Lee), Anti-Federalist #16
"The safest and best restriction, therefore, arises from the nature of the cases in which Congress are authorized to exercise that power [of suspending habeas corpus] at all, namely, in those of rebellion or invasion. These are clear and certain terms, facts of public notoriety, and whenever these shall cease to exist, the suspension of the writ must necessarily cease also." - Francis Dana, presenter of the Constitution to the Massachussetts ratification convention
"The decision that the individual shall be imprisoned must always precede the application for a writ of habeas corpus, and this writ must always be for the purpose of revising that decision, and therefore appellate in its nature. But this point also is decided in Hamilton's case and in Burford's case. If at any time the public safety should require the suspension of the powers vested by this act in the courts of the United States, it is for the legislature to say so. That question depends on political considerations, on which the legislature is to decide." - United States Supreme Court, Ex Parte Bollman & Swartwout, authored by Justice John Marshall, 1807
"Those respecting the press, religion, & juries, with several others, of great value, were accordingly made; but the Habeas corpus was left to the discretion of Congress, and the amendment against the reeligibility of the President was not proposed by that body." - Thomas Jefferson, Autobiography, 1821
"The Constitution seems to have secured this benefit [habeas corpus] to the citizen by the description of the writ, and in an unqualified manner admitting its efficacy, while it declares that it shall not he suspended unless when, in case of rebellion or invasion, the public safety shall require it. This writ is believed to be known only in countries governed by the common law, as it is established in England; but in that country the benefit of it may at any time be withheld by the authority of parliament, whereas we see that in this country it cannot be suspended even in cases of rebellion or invasion, unless the public safety shall require it. Of this necessity the Constitution probably intends, that the legislature of the United States shall be the judges. Charged as they are with the preservation of the United States from both those evils, and superseding the powers of the several states in the prosecution of the measures they may find it expedient to adopt, it seems not unreasonable that this control over the writ of habeas corpus, which ought only to be exercised on extraordinary occasions, should rest with them. It is at any rate certain, that congress, which has authorized the courts and judges of the United States to issue writs of habeas corpus in cases within their jurisdiction, can alone suspend their power" - William Rawl, A View of the Constitution of the United States, Chapter 10, 1826
"It would seem, as the power is given to congress to suspend the writ of habeas corpus in cases of rebellion or invasion, that the right to judge, whether exigency had arisen, must exclusively belong to that body." - Justice Joseph Story, Commentaries on the Constitution of the United States, Book 3, Chapter XXXII, § 1336, 1833
"With such provisions in the constitution, expressed in language too clear to be misunderstood by any one, I can see no ground whatever for supposing that the president, in any emergency, or in any state of things, can authorize the suspension of the privileges of the writ of habeas corpus, or the arrest of a citizen, except in aid of the judicial power. He certainly does not faithfully execute the laws, if he takes upon himself legislative power, by suspending the writ of habeas corpus, and the judicial power also, by arresting and imprisoning a person without due process of law." - Chief Justice Roger Taney, Ex Parte Merryman, United States Circuit Court, 1861
"There has been much discussion concerning the question whether the power to suspend the "privilege of the writ of habeas corpus," is conferred by the Constitution on Congress, or on the President. The only judicial decisions which have been made upon this question have been adverse to the power of the President." - Justice Benjamin R. Curtis, Executive Power, 1862