Let's not play word games. Bush isn't a literal dictator - the word is used figuratively to describe his abuses of power, and the failure of the Congress to perform its duties to stop his abuses, because the same party is (was) unified to put their power first and the law second. And Julius Caesar, a dictator, had a Senate; they're not mutually exclusive.
The republicans have appointed some atrocious justices who are radicals gutting the constitution, making things worse.
The Congress and 4 members of the Supreme Court are not providing the proper check on the president, raising the 'dictator' issues.
The list of how they do so is long, for one example, when they lost a vote in Congress on a bill that would give $150 in windfall profit to their #1 donor industry, they did something unprecedented in 220 years of Congress, and held the Congress open all night, just ignoring the vote time being over, and went and twisted arms on the floor, waking the president and passing around a cell phone with him on the other end, asking members to name their price to switch their vote, and they pulled the votes needed.