A- Well, to candidates in an electoral campaign
:If I am the president I will pave the road to the moon.When I am president, I will work to ensure that all of our kids are treated equally and protected equally. Every action I take, I will ask myself, 'Does this make life better for young Americans in Baltimore, Chicago, Detroit, Ferguson, who have as much of a right to live out their dreams as any other child America?'
Read more at: https://www.brainyquote.com/quotes/donald_trump_754616
If I am the president is used by candidates, they may be voted or not but they are saying that "as if they are".
B - As for people saying that in a general way, say - thinking of that as a remote or (almost) impossible thing, they will use the conditional
"if I were..."If I were president I would strive to accomplish these three major things. First, I would strengthen our educational system, second, I would make certain that everyone has equal and fair treatment in our society, and lastly, I would secure our borders.
If I were president, I would also make sure that everyone in this country was treated equal and fair.
The later examples (item B) were taken from a student essay on the Web.