The Caribbean side bowled out the USA for 128 in the clash of the tournament co-hosts at Kensington Oval and then rattled off the target in 10.5 overs with local boy Hope smashing eight sixes as West Indies finished on 130-1.
The win keeps West Indies in the hunt for a place in the semi-finals and leaves the USA, with defeats in both their Super Eights games so far, on the brink of elimination.
Spinner Roston Chase did the main damage with the ball for West Indies with 3-19 in his four overs while Andre Russell also chipped in with three wickets.
But, aware of the need for a strong run-rate in the qualification scenarios, Hope went on the attack from the outset, reaching his half-century in just 26 balls.
West Indies, beaten by England in their opening Super Eights game, now have their destiny in their own hands - if they beat South Africa in their final Group 1 game on Sunday they will make it to the last four.
West Indies have a better net run rate than South Africa meaning they would advance with a win over the Proteas regardless of the outcome of England's final game against the USA.
Hope's aggressive strokeplay helped the home side reach 58-0 in the six-over powerplay with the opener, who was not in the side in the early group stage games, scoring 42 of them.
It was merciless hitting from Hope who struck 12 boundaries and was helped at the end by Nicholas Pooran who joined in the fun with 27 off 12 balls including three sixes.
Hope sealed the victory with his final six, smashing Saurabh Netravalkar over long off to the delight of the home crowd.
There were some brutal bowling figures from the Americans with Miland Kumar going for 22 off his sole over which saw him hit for three sixes.
Barbadian Chase, whose figures were a career-best in T20I games, was delighted with the emphatic performance.
"To do it at home is a great feeling, with my parents and my friends watching. It's something we talked about in the team meeting that if we don't get too many wickets in the powerplay, it's on the spinners to come back and pull the game back and that's what we did today," he said.
"It's our destiny and our goal to win the World Cup so anyone we play we have to beat from here to go win it," he said.
South Africa are top of the group with the maximum four points from their opening two games while England are level with West Indies on two points but with a worse run rate than the Caribbean side.
