The phrase "preeminent role" means having the highest or most important position or influence in a certain area or field. It refers to being the top or most distinguished in terms of importance, authority, or expertise. Full definition
«Given China's preeminent role in the international energy markets, the huge interest generated by the Shanghai Free Trade Zone and the price differential between onshore and overseas energy markets, the establishment of INE as an international trading platform will have considerable significance both globally and regionally,» Linklaters says. (gfmag.com)
The preeminent role that leading legal scholars would grant to the courts - and thus to the state - to define social values would undermine the value - constitutive role of intermediary institutions. (firstthings.com)
The Church reacted to the heterodoxy of the 5th century «Sicilian Briton» (Pelagius) and subsequent Semi-Pelagian followers who over-emphasised the power of human will, by asserting the preeminent role of grace. (faith.org.uk)