Why did Democrats do well in Western Texas in the 1970s

[OSR stands with Israel]

I get why they did well in Eastern Texas as the Rural South was Solidly Dem then but why did they do very well in Western Texas during that era(Briscoe did very well there in 72, Smith and Bentsen did well there well in 70 etc) given that the Rural West was already solidly GOP by the 70s and Western TX is basically more of a rural Westen State than a Rural Southern One

[Frenchrepublican]

Because at that time many voters were prone to vote R at the presidential level even if they were still voting D at the congressional level

[Indy Texas]

I get why they did well in Eastern Texas as the Rural South was Solidly Dem then but why did they do very well in Western Texas during that era(Briscoe did very well there in 72, Smith and Bentsen did well there well in 70 etc) given that the Rural West was already solidly GOP by the 70s and Western TX is basically more of a rural Westen State than a Rural Southern One

That's really only true of the Panhandle.

West Texas was by and large settled by people from East Texas and the South. In many cases, they wanted to start over after the Civil War. West Texas didn't attract Yankee and immigrant German homesteaders the way Kansas/Nebraska/the Dakotas did.

Dolph Briscoe was from West Texas (Uvalde) and was a conservative rural Democrat so it stands to reason he appealed to people there.

Political realignments generally start at the presidential level and then work their way down the ballot over time. West Texas started voting for Republican presidential candidates with Eisenhower, but they were still voting for their Democratic senator/congressman/county judge/sheriff.