“Could politics ever be anything but politics, practical, cynical, compromised, ugly?”

Speech in the U.S. Senate (2018)

Revolution in Poetic Language (1984), p. 17

Circulated in "A Coil of Rage" http://www.snopes.com/politics/obama/coilofrage.asp, a 2011 mass e-mail attributing several fabricated quotations to Obama.
Obama actually wrote, in The Audacity of Hope, p. 261:
In the wake of 9/11, my meetings with Arab and Pakistani Americans, for example, have a more urgent quality, for the stories of detentions and FBI questioning and hard stares from neighbors have shaken their sense of security and belonging. They have been reminded that the history of immigration in this country has a dark underbelly; they need specific reassurances that their citizenship really means something, that America has learned the right lessons from the Japanese internments during World War II, and that <span style="color:gray">I will stand with</span> them <span style="color:gray">should the political winds shift in an ugly direction</span>
Misattributed

Source: The Magic Mountain

Source: The Windup Girl (2009), p. 280

The Education of Henry Adams (1907)

[2014-11-09, Television series, Face the Nation, CBS], quoted in [2014-11-09, George W. Bush: ‘You have to earn your way into politics,’ nothing ‘is ever given to you’, David Edwards, Raw Story, http://www.rawstory.com/rs/2014/11/george-w-bush-you-have-to-earn-your-way-into-politics-nothing-is-ever-given-to-you/, 2014-11-22]
2010s, 2014

Speech in Belfast (5 March 1981) http://www.margaretthatcher.org/document/104589
First term as Prime Minister