It does not mean "to live in a cave" as do the primitives whom the government of Bush II said did 9/11.
No, it is a meaning that has developed downstream from the advent of the "tit for tat" era of American politics.
That era is a time which began shortly after accountability died, a time when lobbyists are considered to be the constituents or base of political action thinking in the halls of Congress, in the White House, and increasingly in the Courts.
The government "caves in" to the interests of the money brokers (banksters) who are too big to fail and too big to jail, leaving wee the American people out in the cold.
One recent example, among many, is the way the banksters have gotten away with plundering the American people:
But some officials with experience sitting across the negotiating table with major banks say the government is making a critical miscalculation that jeopardizes the public interest by seeking a deal before amassing a credible threat of successful prosecution: In essence, they say, the government would give servicers a blanket pass for widespread alleged acts of fraud while extracting too little in return and operating from a relative position of weakness.(Foreclosure fraud). The banksters are the lackeys for MOMCOM, the plunder master, plundering their own nation under the guise of giving that nation it's freedom!