The Mexican Proposition — Matt Chisholm

The Mexican Proposition was the creation of a new state comprising Northern Mexico and the southwestern United States -- the Republic of the Rio Grande. It would stretch from Louisiana to the Pacific.
Brigand and murderer Porfirio Rojas and his band of traitors raised the new flag and relied upon a secret weapon for victory. They were opposed by three men and a girl -- Doke Struther, the millionaire's son who gambled his life without question, George McMasters, half-Cheyenne and true to his word, Joe Blade -- and Charity Clayton, as brave as she was lovely. Their job was to defeat the new republic … or die trying!

Peter Christopher Watts
(19 December 1919 -- 30 November 1983)
… is the author of more than 150 novels, is better known by his pen names of “Matt Chisholm” and “Cy James”. He published his first western novel under the Matt Chisholm name in 1958 (Halfbreed). He began writing the “McAllister” series in 1963 with The Hard Men, and that series ran to 35 novels. He followed that up with the “Storm” series. And used the Cy James name for his “Spur” series.