There is an Islamic Party working on establishing the khilafah
Of course, it'll take almost everyone's support to re-establish the khilifah
http://www.hizb-ut-tahrir.info/info/...s_en/entry_266
Their strategy is to use diplomacy rather than fighting. They are doing it like the Prophet began the khilafah. The Prophet (sws) looked for a pledge to him from leaders. It was finally in Medina, the Prophet (swt) found leaders to pledge to him and lend their support.
Hizb I believe is doing the same. They are looking for a country to pledge and lend their support to Muslims. That's where Muslims can establish themselves at first, ultimately after a call to migrate to that land.