U.S. Senate Democrats, showing consensus on the need to address climate change, spoke in a marathon that ended early Tuesday before legislative business began. The overnight series of floor speeches lasting more than 12 hours by 30 senators began Monday after votes were taken designed to demonstrate that the chamber's Democrats reached consensus on the need to address climate change, Politico reported. Taking a page from Sen. Ted Cruz's 21-hour filibuster against the Affordable Care Act -- in which the Texas Republican read Dr. Seuss' "Green Eggs and Ham" to his children -- Democrats cited Dr. Seuss' "The Lorax," which chronicles the plight of the environment, the Hill said. Sen. Ed Markey, D-Mass., was the first to cite the "The Lorax," reading: "'Unless someone like you cares a whole awful lot, nothing is going to get better, it's not.' Sen. Brian Schatz, D-Hawaii, said the all-nighter was an "opening salvo" to prove "that we're taking this seriously and there is a stirring in the Senate around this issue," Politico said. Absent, however, were moderates such as Mary Landrieu of Louisiana, Mark Begich of Alaska, Mark Pryor of Arkansas and Kay Hagan of North Carolina -- all of whom are considered vulnerable in November's midterm elections. Democratic Sen. Joe Manchin, who represents coal mining regions of West Virginia, skirted the question when asked if he thought there was room for moderate senators to make their case as part of Monday's debate, Roll Call said. "Well, you know, I would hope so," Manchin said. "They have the right to do whatever they want to do. Maybe they want to go in a different direction, I don't know. I'm fine." Senate Minority Leader Mitch McConnell, R-Ky., chided the effort Monday afternoon, calling it an insult to coal workers suffering because of President Obama's climate policies, Politico said. "Tonight you're gonna hear 30 hours of excuses from a group of people who think that's OK, that that's just OK that we have a depression in Appalachia," said McConnell, himself in a tough re-election bid. "Well, it's not OK. It's cruel."