| To some neoclassical economists, the Pareto criterion is the unchallengeable linchpin of welfare economics. |
| The demise of the USSR, they declared, created for the United States the opportunity to establish an unchallengeable global hegemony. |
| The U.S. was so pre-eminent in military power as to be unchallengeable in any serious way, but it was also widely admired and emulated. |
| The U.S. military was so superior as to be virtually unchallengeable on the field of battle. |
| The President's rule is effectively unchallengeable, though, even without his party's huge parliamentary majority. |
| Scripture used in this way, with supposed supernatural authority, is unchallengeable. |
