Johnson hoped that a coalition of Democrats and conservative Republicans could win control of Congress in the 1866 elections, or at least enough seats to allow the president to wield his veto power effectively.  Upon that electoral foundation, he wanted to construct a new political party.  A major obstacle to the latter was that conservative Republicans, such as Seward, and Democrats, such as Doolittle, agreed on few issues other than a shared opposition to Radical Reconstruction.  In order to attract moderates, there was no direct criticism of the Fourteenth Amendment in the convention call, a point that fooled few but disturbed some of Johnson's advisors nonetheless.  

Republican condemnation of the convention call was harsh, and on July 12, the Republican congressional caucus passed a resolution that effectively ousted any Republican who took part in it.  The only "no" vote was cast by Congressman Henry Raymond, the founder and publisher of The New York Times, who had also been the only House Republican to vote against the override of Johnson's veto of the Civil Rights Act.  In fact, Raymond organized the National Union Convention and served as its chairman.  In retaliation, Republicans in his district refused to renominate him for Congress, and few other Republicans attended the convention because the movement’s opposition to the Fourteenth Amendment and dominance by Democrats repelled many moderates and even conservatives.

At the president's behest, Senator Doolittle wrote cabinet members in mid-July to solicit their formal endorsement of the National Union Convention.  Seward, Navy Secretary Gideon Welles, and Treasury Secretary Hugh McCulloch complied, but Attorney General James Speed, Postmaster General William Dennison, and Interior Secretary James Harlan, all resigned rather than submit.  Like the three who resigned, War Secretary Edwin Stanton abhorred the convention as an organization consisting mainly of former Copperheads (Peace Democrats) and Confederates.  However, Stanton decided to stay in the cabinet in order to resist the president's effort to thwart enforcement of Congressional Reconstruction.

The featured cartoon caricatures scenes from the National Union Convention of August 14-16.  The center circle mimics the opening procession led by Governor Darius Couch (right) of Massachusetts and Governor James Orr (left) of South Carolina, linked arm in arm.  As cartoonist Nast writes, the incident reportedly filled "the eyes of thousands with tears of joy" as the chief executives of the first rebel state ("first gun") and the leading Unionist state ("first blood") symbolized sectional reconciliation.  Surrounding the two governors, a crocodile and copperhead snake shed "crocodile tears" (center and top), as does President Johnson (lower-center) and a fox and goose (top; animal rivals and symbols of the Democratic Party).

Doolittle, Randall, Blair, and Orville Browning (the new Interior Secretary), appointed themselves as an executive committee to maintain an atmosphere of harmony and moderation.  At the top of the cartoon, "the spirit of concord and brotherly affection" is manifested by former Confederates and Unionists kissing, including Raymond (in dark suit on the upper-far-left), and by Randall (upper-right) kicking two leaders of the former Copperheads, Congressmen Fernando Wood of Ohio (left) and Clement Vallandingham of Ohio (right), out of the convention.  The executive committee refused to recognize the two men's credentials as elected delegates.  The "patriotic sentiment and unbroken harmony" in the lower panel shows how Doolittle (lower-right) has padlocked the mouths of those who might dissent.

The National Union Convention praised President Johnson, denounced the Radical Republicans, and encouraged the electorate to vote only for candidates supporting the immediate readmission of all the former Confederate states.  Delegates and their supporters characterized the convention as a great success, while Republican opponents (like Nast) ridiculed it.  On August 28, Johnson and key advisors went on a campaign tour (the ill-fated "swing 'round the circle"), which generated more negative publicity and political opposition for the president.  Harper's Weekly published this Nast cartoon while Johnson was in the middle of his trip.  In the fall elections, Republicans won a large majority of seats in Congress, more than enough to override any presidential veto.