The worst thing the Dallas Cowboys can do at the trade deadline is nothing. Either sell some players on expiring contracts for draft capital, or make one or two moves to improve the defense. Don't spectate from the sidelines while NFC rivals push the envelope.
Jerry Jones is the ultimate seller of hope, so the Cowboys will likely be buyers. To what extent remains to be seen. In terms of the defensive line, if Maxx Crosby, Trey Hendrickson, Jermaine Johnson, or Jaelan Phillips can be had at a fair price, Jones shouldn't think twice about pulling the trigger.