Answer:
marked by or showing lethargy, passivity, or blameworthy indifference
Step-by-step explanation:
Supine means, among other things, 'exhibiting passivity'; therefore, 'lying supinely' would be correctly defined as 'showing lethargy, passivity, or blameworthy indifference'.
The supporting evidence in the text:
The phrase lying supinely on our backs is linked by the coordinating conjunction and, (which is used to join equal ideas), to the following: hugging the delusive phantom of hope, until our enemies shall have bound us hand and foot. It definitely suggests passivity and indifference.