In the link below, Fr. Z is calling on the SSPX to crawl on their knees to accept the offer that Benedict XVI put forth for reconciliation / regularization.  

What would prevent the pope elected some time in March from simply declaring the agreement null and void?  Or altering it to make the arrangement that the SSPX would become strictly a seminary for traditionalist priests who must then become incardenated into local parishs at the local bishops request.  

Why do the concilliarists keep saying that future popes may not be open to making a deal with the SSPX?  What would prevent those future popes from again removing all the benefits of regularization in the same manner that Paul VI did with Archbishop LeFebrvre?  

http://wdtprs.com/blog/2013/02/sspx-reacts-to-popes-announcement/