Understand a few simple facts about Islaamic Politics:
1) The current Democratic system prevalent in the world is totally un-Islaamic,
2) In Islaam, we have qualified voters to elect qualified candidates to produce qualified leadership,
3) The Ameer is not a Dictator,
4) He is not above Islaamic Law and he is counseled by the Shurrah,
5) There is no desire for post and power in Islaamic Politics,
6) A female cannot become a Ruler of the Nation,
7) No law can be made which runs contrary to Islaam,
8) The purpose of the Islaamic Government is to establish the basic tenets of Islaam,
9) The Imaan, life, property, sanity, and honor of all will be protected,
10) The non-Muslims (Zimmis) will pay Jizya (protection fee) to have their lives, property, and honor protected,
To know the actual process of how the Khalifa is brought into position we will have to go back to the Era of the Khulafa-e-Rashideen:
1) Hadhrat Abu Bakr (R.A) became a Khalifa via the allegiance of those who had the ability to decide;
2) Hadhrat Umar (R.A) became the Ameerul Mu'mineen via nomination by Hadhrat Abu Bakr (R.A.);
3) Hadhrat Uthmaan (R.A) became the Ameerul Mu'mineen via the process of elimination from the 6 great Sahabah (R.A) that Hadhrat Umar (R.A) nominated;
4) Hadhrat Ali (R.A) became Ameerul Mu'mineen via natural choice as the most Senior left.
5) Hadhrat Muawiya (R.A) became the Ameerul Mu'mineen by Hadhrat Hassan (R.A) ceding the Rulership to him;
As seen from the above, the Shariat has clearly outlined the methodology in which the Khalifa should be brought into power.
In the current claim no proper Shaari procedure or process was adhered to.
In an Islaamic country the Ulema and those who have decisive powers (Ahle Rai) will elect the parliament (Governing Shurrah Body). From the Shurrah the Ameer will be chosen.
Now that Ameer cannot unilaterally declare that he is the Khalifa of the whole Muslim World. For that you need many/most of the Islaamic countries Ameers to gather and choose the Khalifa of the Muslim World who will then implement Sharia across all Islaamic countries.
So there is a process. Otherwise every other Muslim Ruler, fit or unfit, capable or incapable, pious or sinner will become a claimant. Chaos and pandemonium will break out.
Yes, there definitely is a need to re-establish the Khalifaat; we make Du'aa it happens.