It is these western governments themselves who define what groups are terrorist groups. They both make the definitions of terrorism and decide what groups fall into these definitions. For example the United Kingdom regarded the IRA (Irish Republican Army) as being a terrorist group while the United States did not consider them a terrorist organisation. [1] Therefore if these countries wished to deal with and provide financial aid to a new Palestinian government, even if it was the political arm of a terrorist organisation they could simply redefine it, as would almost certainly be the case if the terrorist organisation was perceived as doing something that is in the interests of these western nations.  [1]