The phrase "a difficult force" is correct and usable in written English.
It can be used to describe a challenging or formidable influence or power in various contexts, such as physical, emotional, or social situations.
Example: "The storm proved to be a difficult force, uprooting trees and causing widespread damage across the town."
Alternatives: "a challenging power" or "a formidable influence."
But the pull to see elephants up close has proved a difficult force to overcome.
But the lure of tourist dollars is proving a difficult force to counter.
But the Rev. Reginald T. Jackson, executive director of the Black Ministers Council off New Jersey, said that you don't have to be skilled in the art of crystal ball reading to know that the political influence of the State Police can be a difficult force to overcome.
But incumbency is a difficult force to beat in New York (or anywhere else in America), and the litany of failures listed above would count as policy achievements in today's Republican Party.
"There is a radical international jihad, with some influences of midlevel Al Qaeda operations, that will remain a very difficult force for us for many years," a senior government official in Washington said.
The Guards are thought to control at least a third of the economy, owning vast conglomerates and banking empires, with front companies abroad which will be an extremely difficult force for the West to topple.
Giavotella ranged far to his right to field the ball, but instead of getting the easy out at first, he went for an extremely difficult force at second.
"The fact that we haven't had a clean sheet for 14 games now, we needed to change something, I thought we coped well today with a difficult strike force.
But unless Mugabe makes concessions, Tsvangirai will be left in a difficult position, forced to choose between accepting a weak position in government and holding out, leaving the country's dire socioeconomic situation to worsen.
But it has also left Latin Americans in a difficult position, forced to choose between one country accused of dictatorship and another being called an empire — or to simply condemn both.
The case was a difficult one, forcing the court to weigh the free-expression rights of those who burn crosses against the right of their victims not to be physically intimidated and threatened with harm.
