Is it permissible to pay Zakat to campaigns for the relief of the Syrian people?

If those in charge of relief campaigns are trustworthy and deliver the Zakat to its rightful recipients, then there is no harm in giving them Zakat to deliver it to the Syrian displaced people. This falls under the permissible delegation (Tawkil) in distributing Zakat. The poor and needy Syrian refugees are among the rightful recipients of Zakat.