The album title is a reference to the USS Monitor, the first ironclad warship commissioned by the United States Navy, and the closing track, "The Battle of Hampton Roads," refers to the battle between the Monitor and the CSS Virginia, which took place on March 8–9, 1862; according to the band, "Releasing this record is our way of celebrating the 148th anniversary of this historic event." There are numerous references to early Billy Bragg songs such as some lyrics in "A More Perfect Union" and the song "Richard II". "A More Perfect Union" also includes references to the band's New Jersey roots as well as riffs on the lyrics of Bruce Springsteen, another New Jersey native. The album features guest appearances by members of Ponytail, Wye Oak, Hallelujah The Hills, Felice Brothers, Spider Bags, Vivian Girls and The Hold Steady.
The Monitor debuted at number 7 on the Billboard Heatseekers chart.
This album received a Metacritic score of 82 out of 100, signaling universal acclaim. Pitchfork Media included the album in their list of top albums of 2010, at #10 while Spectrum Culture gave the album its #1 position. "The Monitor" was named Exclaim!'s No. 20 Pop & Rock Album of 2010.
The album was recognized as number 30 of The 100 Best Albums of the Decade So Far by Pitchfork Media in August 2014.