They both lie for a living

Politicians who write novels.

Mario Vargas Llosa, Norman Mailer and Gore Vidal, among others, have been political candidates in the past. Upton Sinclair even sought to become governor of California. But the political winds typically blow in the other direction: For some reason, a good many prominent politicians have eventually written novels, including Jimmy Carter, Ed Koch, Gary Hart, Newt Gingrich, William Cohen, Barbara Mikulski, Raymond Flynn and even Winston Churchill. If tyrants count as politicians, we can add Saddam Hussein to the list, although it's nice to report that probably the most famous and accomplished politician-novelist, Benjamin Disraeli, was duly and democratically elected.

Further reading: The early novels of Benjamin Disraeli; a review of Jimmy Carter's novel, The Hornet's Nest; and the two Winston Churchills.