Michael never was Emperor of Russia. While he had the opportunity to ACCEPT the Imperial Power granted to him by Nicholas II, he did not. That is critical. He chose otherwise and thus extinguished the Imperial Line.
Of course Michael was immediately Emp. of Russia the moment the ex-Emp. Nicholas II lifted his pen off the document that was his abdication. Russia wasn't following any US presidential laws. Russia was following laws of Peter I's. And, Russia was NEVER without a Emp. for one second. This means that Michael was immediately Emp. of Russia. Being Emp. wasn't a popular vote kind of thing. It was through the inheritance laws of the crown. I forget the date but when Nicholas II allowed Michael to return to Russia and take up the position as second in line to the succession behind Tsarvich Alexei, all kinds of official papers were signed, including the ones that eliminated any of Michael's children as being heirs to the throne. This is when GD Kyril legally became successor after Michael. If Alexei should survive then his children would have been his successors.
There are legal questions if Nicholas II could set aside his son and make Michael his successor. As far as I know, this was never taken into any court for any kind of legal, because of the change of politics under the Duma, then the Prov. Govt. and then the Bolshevik Regime.
Since no one of importance disputed the successor to be that of Michael, then he for all sakes and purposes was the uncrown Emp. under the Imperial Laws.
Legally, Nicholas II had already dealt with the Duma on 11 March 1917. He had officially demanded that they were to close their doors. They were the first Revolutionary Movement. They did not close their doors and were the ones with the help of the generals around Nicholas II to isolate him and give him no choice but to abdicate.
The Prov. Govt. was part of the Second Revolutionary Movement and due to this definition, was, also, outside the Imperial Law on 12 March 1917. It was headed by Prince Lvov. The Consitutional Democract was Paul Miliukov. Minister of Foreign Affairs was Aleander Guchkov. The minister of Justice was the Socialist Kerensky.
Nicholas II was still in power and still the Emp. of Russia.
Nicholas II abdicated on 15 March 1917 in favor of his brother Michael.
>>In the days of the great struggle against the foreign enemies, who for nearly three years have tried to enslave our fatherland, the Lord God has been pleased to send down on Russia a new heavy trial. Internal popular disturbances threaten to have a disastrous effect on the future conduct of this persistent war. The destiny of Russia, the honor of our heroic army, the welfare of the people and the whole future of our dear fatherland demand that the war should be brought to a victorious conclusion whatever the cost. The cruel enemy is making his last efforts, and already the hour approaches when our glorious army together with our gallant allies will crush him. In these decisive days in the life of Russia, We thought it Our duty of conscience to facilitate for Our people the closest union possible and a consolidation of all national forces for the speedy attainment of victory. In agreement with the Imperial Duma We have thought it well to renounce the Throne of the Russian Empire and to lay down the supreme power. As We do not wish to part from Our beloved son,
We transmit the succession to Our brother, the Grand Duke Michael Alexandrovich, and give Him Our blessing to mount the Throne of the Russian Empire. We direct Our brother to conduct the affairs of state in full and inviolable union with the representatives of the people in the legislative bodies on those principles which will be established by them, and on which He will take an inviolable oath.
In the name of Our dearly beloved homeland, We call on Our faithful sons of the fatherland to fulfill their sacred duty to the fatherland, to obey the tsar in the heavy moment of national trials, and to help Him, together with the representatives of the people, to guide the Russian Empire on the road to victory, welfare, and glory. May the Lord God help Russia!<<
Michael became Emp. Michael of Russia on 15 March 1917, 3:05 P.M. in every way with or without the crown on his head.
AGRBear