The ISIS war might cost U.S. taxpayers tens of billions. Or it might not. At this point, the White House still isn’t releasing an approximate figure.  

CQ Roll Call asked White House Press Secretary Josh Earnest at today’s press briefing if he had a ballpark estimate, and he didn’t have one handy. The Office of Management and Budget hasn’t provided one yet either — we’ve been asking.  

An outside expert has estimated the war could cost $1.5 billion a month , about the cost of the NASA budget. It had been costing $7.5 million a day through August, before President Barack Obama dramatically ramped up the mission.  

But the cost will also depend on Obama’s strategy, and how successful he is at courting the scores of coalition partners to shoulder either the burdens of military action, or providing cash.  

“One way that countries can participate in this coalition and contribute to this broader effort is financially,” Earnest said Monday. The first Gulf War in 1991 was mostly paid for by allies, unlike the Iraq and Afghanistan wars.  

Obama has some leeway from Congress, which provided him billions more in war funding than he sought in the continuing resolution that expires Dec. 11 , even though they ducked an explicit vote authorizing the war .  

And the costs should certainly be much cheaper than a ground invasion, although equipping and training someone else’s boots on the ground won’t be free.  

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