Let’s say the ECB decides to buy Spanish and Italian bonds to keep the rates low. This program would merely offer a temporary respite. The economic conditions in the periphery are what is causing the run on sovereign bonds. If Spain and Italy decided to undergo free-market reforms coupled with dramatic changes to their entitlement programs, they would put themselves on a course to solvency. The panic would end shortly after the reforms were implemented.
As long as Spain and Italy choose to make cosmetic changes, investors are right to question whether they will be paid back. If the ECB rolls out a bond buying program during these conditions, investors will merely use the program as their exit. Sooner or later, the ECB will be the only entity financing Spain and Italy if the whole process is allowed to continue to its inevitable conclusion…just like Greece.