Civi Ajax API Search by Multiple Tags

Question

As sort of a followup to this question. I am trying to retrieve all the contacts who have tag:5 AND who have tag:7. I tried the following code:

CRM.api3('Contact', 'get', {
  "sequential": 1,
  "tag": [5,7]
  "return": ["tag","first_name"]
}).done(function(result) {
  // do something
});

However, this returns all the contacts who have tag:5 OR tag:7. Is there any way to do this through the API? The only other solution I can think of is sifting through the objects using some client-side javascript.