When President Trump starts asking for judicial writs on third parties

How is Kagan going to rule?  Does she favor executive authority, interpreted broadly.  How would she rule now, it's Obama pushing the button.  2017, Apple vs DOJ; right of Swamplanders to compel a third party, for actions taken before the gap was filled.  So, Kagan, what say you, can Obama and Trump compel, after the fact, by requesting a writ.