'powerful leverage' is correct and usable in written English.
It is generally used to indicate a means of gaining a strategic advantage or increasing one's capacity for success. For example, "The company used their large customer base as powerful leverage in negotiations with their suppliers".
While the task force itself does not have subpoena power, the regulatory agencies involved hold powerful leverage through their ability to cut off financing to groups that fail to comply.
But the two American giants have powerful leverage.
It gives us powerful leverage on the market".
The Administration saw the prospect of growing dissatisfaction within the military as powerful leverage.
(And you've overlooked the powerful leverage of your new baby, too).
Universal appears to have powerful leverage, making its demands more than just the usual negotiating posturing.
The $72 million in federal money, therefore, could generate up to $576 million in loans — a powerful leveraging effect that was the goal of the TARP program.
Intel offered a sneak peek of some devices coming out later this year - the OpenPeak tablet was small, sleek and powerful, leveraging their new Moorestown platform.
It was "a total surprise and shock," Abbott's outside lawyer, Mr. Weinberger, would later say in court, explaining that the company was willing to pay because Geneva had such powerful negotiating leverage.
Santos also said he would meet with Colombia's opposition, led by former president and senator Álvaro Uribe, a mortal enemy of the FARC who has gained powerful new leverage over any potential attempt to rewrite the peace deal.
The passion and urgency of Corbyn's supporters gives the new leader powerful moral leverage over his reluctant colleagues in parliament, but it doesn't necessarily broaden his room for manoeuvre.
