He demanded the privilege of proving that his people were precisely as loyal Americans as any others

From The Rough Riders by Theodore Roosevelt. Page 31.

There were but four or five days at Tampa, however. We were notified that the expedition would start for destination unknown at once, and that we were to go with it; but that our horses were to be left behind, and only eight troops of seventy men each taken. Our sorrow at leaving the horses was entirely outweighed by our joy at going; but it was very hard indeed to select the four troops that were to stay, and the men who had to be left behind from each of the troops that went. Colonel Wood took Major Brodie and myself to command the two squadrons, being allowed only two squadron commanders. The men who were left behind felt the most bitter heartburn. To the great bulk of them I think it will be a life-long sorrow. I saw more than one, both among the officers and privates, burst into tears when he found he could not go. No outsider can appreciate the bitterness of the disappointment. Of course, really, those that stayed were entitled to precisely as much honor as those that went. Each man was doing his duty, and much the hardest and most disagreeable duty was to stay. Credit should go with the performance of duty, and not with what is very often the accident of glory. All this and much more we explained, but our explanations could not alter the fact that some had to be chosen and some had to be left. One of the Captains chosen was Captain Maximilian Luna, who commanded Troop F, from New Mexico. The Captain's people had been on the banks of the Rio Grande before my forefathers came to the mouth of the Hudson or Wood's landed at Plymouth; and he made the plea that it was his right to go as a representative of his race, for he was the only man of pure Spanish blood who bore a commission in the army, and he demanded the privilege of proving that his people were precisely as loyal Americans as any others. I was glad when it was decided to take him.