Double Down Meaning

(idiomatic, by extension) To double or significantly increase a risk, investment, or other commitment.

Example: 1999, Frederick Barthelme and Steven Barthelme, Double Down: Reflections on Gambling and Loss, ISBN 9780395954294, page 66:
  He'd bet three thousand and double down to six thousand, all of it hanging on the turn of the next card.
2007, Peter Beinart, "The Kosovo Conundrum," Time, 12 April:
  Hillary Clinton, John Edwards and Barack Obama all want to get out of Iraq. They all want to double down in Afghanistan.