'decisive interest' is a correct and usable phrase in written English.
You can use it to describe a very strong interest or influence in a situation or outcome. For example, "The decisive interest of the Board of Directors ultimately decided the outcome of the vote."
In Russia today, decisive interest groups — especially business oligarchies that control much of the economy or regional politicians who have their own fiefdoms — dare not publicly engage in the debate over succession, for fear of incurring the Kremlin's retribution.
On Long Island, as throughout the country, executives, economists and analysts are cutting back on growth predictions, tamping down expectations of job expansion and capital investments and calling for decisive interest rate relief from the Federal Reserve, a far cry from the unbridled optimism that prevailed throughout the economic boom.
The trick now will be maintaining that initial engagement into continuing, and decisive interest.
While business angels consider decisive the interest of potential consumers for the product, this aspect is deemed less relevant by the entrepreneur.
The text of the Constitution was not decisive, and the Northern interest was strongly in favor of the latter interpretation.
River basin management can frequently involve decisive situations, when conflicting interests must be resolved.
The decisive events stimulating these interests were the Industrial Revolution and the publication of Charles Darwin's Origin of Species (1859).
The RBI is thus confident that it will be able to keep inflation below 6% by next January, as it has pledged.India's stockmarket rose sharply in response to the news, which investors judged was a decisive turn in the interest-rate cycle.
"I will not tolerate these reports and I have, and will continue, to take decisive action in the interests of learners in Wales," he added.
Clinton wants mandated five-year reviews of trade agreements after ratification, constant monitoring of "compliance" with deals and even more rules tacked to trade accords a decisive step toward putting special interests permanently ahead of the general public interest in economic freedom, albeit refreshingly unambiguous.
Still, the European Central Bank's action today was decisive, even historic -- bringing interest rates down to a level not seen here since at least World War II.
