Humphrey manages to swing California in 68 causing Nixon's Southern Strategy to fail, the Republican party begins to swing more to the moderate/left while still appealing to there pro-business base.
In 72 an unpopular Humphrey leaves office due to Vietnam where an underdog Republican Congressman John B. Anderson wins his parties nomination on a pledge to seek peace in Vietnam while the Democrats nominate radical anti-communist Scoop Jackson.
There is no Reagan Revolution and the Christian Right doesn't become the force it is today.
A trend begins where the Republicans begin to drift more to the center on social issues like civil rights while the democrats drift further to the right on such social issues, while keeping to the left on fiscal issues staying true to there Union base.
The result is a modern day Democratic party that is social conservative but fiscally very liberal and pro-union, Unions being a more political force due to the absence of Reagan, while being very Christian and socially conservative.
While the Republicans become Fiscal Moderates who are socially liberal.
The result is the South staying largely Democratic
Giving us a Democratic Texas.