One difference is that both the White House and Senate are controlled by the same party.
Another difference is that Obama was not allowed to run for re-election, whereas Trump is running for re-election, so that voters can weigh in on the choice, by voting for, or against Trump, as the case may be. Voters would have had to change to weigh in by voting on Obama’s election because he was term limited out at that point.
should read “voters would have had no chance” to weigh in on Obama.