Firstly, the president can do so. Importantly, in that case he can do so simply because he feels it is the right thing to do. It doesn’t matter whether he has the signature of every single deputy in the Iraqi parliament or none; it is his decision alone. It should be stressed that there is no need for the president to present any compelling rationale for having the vote.
Secondly, a fifth of the deputies in parliament (65 MPs) can also ask for a questioning of the PM (istijwab) followed by a no confidence vote. In that case, however, they need to go directly to the parliamentary speaker (Usama al-Nujayfi). Talabani has no role whatsoever in that route to a no confidence vote.
In other words, the signatures to Talabani are no more binding than an opinion poll. Talabani may listen to them if he likes to, or he may reject them and ask them to work via a 65-member petition instead.
This is why it is so strange that Maliki has initiated a procedure of investigation of these basically valueless signatures. One possible explanation is that he may want to pre-empt any possible move by his enemies through embarrassing them with charges of fraud. The different reports of the true number of signatories are in themselves perhaps an indication that there may be problems relating to the verification of some of the signatories. Even if this move by Maliki may seem quixotic, it is certainly preferable to the overtly politicised recent ruling by the supreme court on the right of parliament to question ministers.
Iraqiyya claims Talabani has already sent a request for a no confidence vote to Nujayfi. The only thing that is known officially is that Talabani has formed a committee to deal with the question of the authenticity of the signatures.
Constitutionally meaningless it all is, but maybe a way of winning time for players unsure about their next move?