About 100 years after Abraham Lincoln’s death, Dr. Ray Neff, a health sciences professor at Indiana State University with a chemistry background, de-ciphered coded messages left by Colonel Lafayette Baker, Union spymaster. An inventory of Baker’s possessions showed he owned bound volumes of “Colburn’s U.S. Magazine” for the years 1860 to 1865 – with one exception: the volume for the first half of 1864 is not listed in the inventory. Ray Neff had come across the volume from the latter half of 1864. 
Baker’s decoded message from the latter-half volume of Colburn’s U.S. Magazine (1864) told of a coup d’état within the Union itself. “There were at least eleven members of Congress involved in the plot, no less than twelve Army officers, three Naval officers and at least twenty four civilians, of which one was a governor of a loyal state. Five were bankers of great repute, three were nationally known newspapermen and eleven were industrialists of great repute and wealth.” 
De-ciphering Baker’s message, it was learned that the specific names of the members of Congress, military officers, bankers, newspapermen and others could be found in Volume One. But Volume One of Baker’s copy of Colburn’s U.S. Magazine for 1864 could not be located. 
A tentative partial list of the traitors within the Union itself who silently condoned, aided and abetted the assassination of Abraham Lincoln on April 14, 1865, obstructed justice, actively assisted the assassination, and/or allowed a coup d’état government to hold power, is offered below. All are innocent until proven guilty.
A speech given by President Andrew Johnson to a crowd outside the White House on February 22, 1866 included some of the names:
(A voice from the crowd: “Give us the names.”) A gentleman calls for their names. Well, suppose I should give them. (A voice “We know them.”) I look upon them I repeat it, as President or citizen as being as much opposed to the fundamental principles of this Government, and believe they are as much laboring to pervert or destroy them as were the men who fought against us. (A voice “What are the names?”) I say Thaddeus Stevens, of Pennsylvania (tremendous applause). I say Charles Sumner (great applause). I say Wendell Phillips, and others of the same stripe, are among them. (A voice “Give it to Forney.”) Some gentleman in the crowd says, “Give it to Forney.” I have only just to say that I do not waste my ammunition on dead ducks. (President Andrew Johnson, February 22, 1866. 
THADDEUS STEVENS: Thaddeus Stevens, leader of the “Radical” faction of the Republican Party, “warmed into life the brutal instincts of [Edwin] Stanton, [Joseph] Holt and [Lafayette] Baker, to have Lincoln assassinated.” 
CHARLES SUMNER: U.S. Senator from Massachusetts. A leader of the Radical Republicans in the United States Senate during the American Civil War.
WENDELL PHILLIPS: Abolitionist. “It was Phillips’s contention that racial injustice was the source of all of society’s ills.” 
JOHN WEISS FORNEY: Secretary of the United States Senate 1861-1868. One of the foremost in the struggle which resulted in the impeachment of President Andrew Johnson.  Andrew Johnson resisted the coup d’état forces behind the Lincoln assassination. (Background: Resistance of Andrew Johnson, Ersjdamoo’s Blog, July 24, 2015.)
In the decoded messages of Colonel Lafayette Baker, a few other names are given (but not the complete list from the lost Volume One however):
MAJOR THOMAS T. ECKERT: “Be off, Tom, and see to the arrangements,” said Edwin Stanton on the eve of the Lincoln assassination. 
EDWIN M. STANTON: Secretary of War. “It was Thaddeus Stevens, leader of the ‘Radical’ faction of the Republican Party, who had ‘warmed into life the brutal instincts of [Edwin] Stanton, [Joseph] Holt and [Lafayette] Baker, to have Lincoln assassinated.'” 
JOSEPH HOLT: Judge Advocate General of the Union Army. Holt was the chief prosecutor in the 1865 “Trial of the Conspirators.” Holt’s public image was besmirched by the trial and his prosecution of it. 
The diary of John Wilkes Booth, the actual shooter of President Lincoln, gives other names:
JOHN CONNESS: U.S. Senator. He met personally with John Wilkes Booth prior to the assassination. 
JAY COOKE: An American financier who helped finance the Union war effort during the American Civil War. He is generally acknowledged as the first major investment banker in the United States.  Cooke met personally with John Wilkes Booth prior to the assassination. 
THURLOW WEED: Newspaper publisher and Republican politician. Weed met personally with John Wilkes Booth prior to the assassination. 
ZACHARIAH CHANDLER: One of the founders of the Republican Party, whose radical wing he dominated as a lifelong abolitionist. U.S. Senator.  Chandler met personally with John Wilkes Booth prior to the assassination. 
BENJAMIN WADE: A United States Senator during Civil War reconstruction known for his leading role among the Radical Republicans. Had the impeachment of Andrew Johnson in 1868 led to a conviction at trial in the Senate, he would have assumed the presidential powers and duties. 
Another name to include in this infamous list is the head of a committee which met early in 1865:
ELIHU B. WASHBURNE: He headed a congressional investigation, the Washburne Committee, into Civil War cotton smuggling designed to bring down the Lincoln administration through “all the President’s men” Ward Lamon and Orville Hickman Browning. That “soft coup” attempt failed. (Background: Inner Workings of Republican Assassins, Ersjdamoo’s Blog, July 23, 2015.)
A final name for this preliminary list may startle some:
ULYSSES S. GRANT: An excellent military general but a weak politician. Grant’s friend, General William T. Sherman, advised him to avoid Washington and its politics when Grant was promoted to commanding general. Grant was invited by President Lincoln to attend Ford’s Theater on the fateful night of April 14, 1865, but declined the invitation. Had Grant attended, he (and consequently Lincoln) would have been well guarded. Otto Eisenschiml found it odd that Grant declined an invitation from his commander-in-chief. Grant however was subordinate not just to Lincoln, but to the Secretary of War, Edwin Stanton. Two politicians were tugging at Grant, one (Lincoln) said, “Go to the theater”; the other (Stanton) said, “Do not go to the theater.” At that point, recalling his friend Sherman’s advice to avoid Washington, General Grant hopped on a train and left town.
——- Sources ——-
 “Ray Neff Discovers Coded Messages”, by Brian Redman. http://uts.cc.utexas.edu/~wbova/fn/history/lincoln_02.htm See also: Anatomy of an Assassination by John Cottrell. New York: Funk & Wagnalls, 1966.
 “Speech to the Citizens of Washington”, Andrew Johnson, February 22, 1866. http://teachingamericanhistory.org/library/document/speech-to-the-citizens-of-washington/
 “Blowback From Intra-Party Coup d’état”, Ersjdamoo’s Blog, July 17, 2015. https://ersjdamoo.wordpress.com/2015/07/17/blowback-from-intra-party-coup-dtat/
 “Wendell Phillips”, Wikipedia, July 25, 2015.
 “John Weiss Forney”, Wikipedia, July 25, 2015.
 “Inner Workings of Republican Assassins”, Ersjdamoo’s Blog, July 23, 2015. https://ersjdamoo.wordpress.com/2015/07/23/inner-workings-of-republican-assassins/
 “Addenda to the Addenda”, Ersjdamoo’s Blog, July 14, 2015. https://ersjdamoo.wordpress.com/2015/07/14/addenda-to-the-addenda/
 “Joseph Holt”, Wikipedia, July 24, 2015.
 The Lincoln Conspiracy, by David Balsiger and Charles E. Sellier, Jr. Los Angeles: Schick Sunn Classic Productions, 1977.
 “Jay Cooke”, Wikipedia, July 25, 2015.
 “Zachariah Chandler”, Wikipedia, July 25, 2015.
 “Benjamin Wade”, Wikipedia, July 25, 2015.