WASHINGTON (AP) — Once considered untouchable, Social Security is now in play in the debt-ceiling negotiations. And that could mean higher income taxes for many U.S. families in addition to shaved benefits for tens of millions of retirees as they age.Social Security became part of the private discussions between President Barack Obama and Republican House Speaker John Boehner on coming up with "something big" to reduce deficits by $2 trillion to $4 trillion over the next decade. One option includes a new inflation measure for Social Security that could produce savings close to $200 billion through a combination of reduced benefits and higher taxes, White House officials said Thursday.Low- and middle-income families could be hit.The proposal would represent a reversal for Obama.