The editors at The Financial Times also want John Kerry to issue hollow threats on Syria:

If Mr Kerry is to have any diplomatic force in discussions he must be able to threaten an alternative. Mr Assad has cynically exploited the west’s reluctance to intervene to stay in power. This bluff has to be called.

If the U.S. and its European allies have no intention of taking more aggressive measures in Syria, and it still seems that they don’t, no one will take these threats seriously. If Kerry followed this advice, he would be the one bluffing and Assad and the rest of the world would know it. It doesn’t help that the ideas that the editors propose as part of the threat Kerry is supposed to make are thoroughly bad ones that have been repeatedly rejected and discredited over the last two years. “Arm the rebels” is the new fallback position for anyone who wants to advocate for “action” in Syria, but there is never much thought given to whether the proposal makes any sense.

Threatening more aggressive measures at this stage lacks credibility because the proposed measures in question are all so severely flawed, and they have been picked apart so many times that I doubt that anyone still believes they will achieve the desired goals. Threatening to arm Syrian rebels directly wouldn’t make it easier to reach a negotiated settlement, since following through on that threat would prolong and intensify the fighting. As a general rule, governments should not threaten to take actions that they have already considered and rejected as unwise. It makes them appear ridiculous and achieves nothing.