TIMELINE:
Texas announces it is seceding from the USA
US announces that the states cannot secede and declares it will intercede to stop the process
LA announces it is joining TX
US establishes a land, sea and air blockade of TX and LA and threatens to use deadly force to back it up
OK announces it is joining TX and LA
TX “nationalizes” all US property and resources inside the TX border, including military bases and installations. (there are some minor firefights, but nothing serious)
TX has the military capability to stand off the US forces, specially when a lot of them will be reluctant to fire on TX citizens. (there are a lot of big Army and Air Force bases inside TX with a lot of Texans involved - any military personnel wishing to stay loyal to the US would be escorted to the border)
KS, NE, MS and AL announce they are joining the states leaving the US
TX declares all US agreements that involve TX resources null and void and announces the intention to re-negotiate any deals or treaties.
US backs down on the land and air components of the blockade, but makes it difficult and expensive to get into or out of TX and confiscates shipments and imprisons TX residents who leave TX.
TX retaliates in kind.
Border skirmishes break out and lives are lost, but nothing serious is accomplished in terms of military objectives.
TX must break the naval blockade to restore oil shipments. TX Air Natl Guard (now TX Air Force) planes attack US Navy ships in the Gulf of Mexico, lose several planes, but sink several ships. The blockade is fractured but not destroyed. (if only TX had a couple of good submarines)
ND, SD, AR, MO, KY announce they are joining the states leaving the US
US threatens to bomb the oil refineries at Galveston and Houston if the attacks continue.
TX threatens to escalate to using nukes if US bombs TX resources. (note that TX has the only nuclear weapon assembly plant in the US)
GA, SC, WV, WY, MT, ID, UT, AK announce they are joining the states leaving the US
At this point, the military blustering cools off somewhat and the conflict turns into primarily an economic standoff. TX needs the shipping lanes open. US needs TX oil. (there are many other resources involved too, but these are the primary ones)
TX is nearly self-sufficient by itself and if other states are included, the group can become self-sufficient, but without oil sales outside the borders, their economy suffers greatly. US economy is also crippled without TX oil, grain from KS and NE and other resources, but can continue.
If TX has to go this path alone, it may not work, but if other states join in, there is a tipping point where the US cannot effectively enforce an embargo across too many borders and too many miles and needs to sue for peace. US could allow the secession and negotiate deals and treaties with the new country, or offer concessions to get TX and the others to stay within the Union. Political upheaval inside the US could force the second option.
As long as you are dreaming in the timeline, you should really include TN in there. This is especially true if you include Kentucky.
If MO and KY go, I’ll personally lead the effort to bring IL south of I-80.
I can’t picture the Liberal fighting
If there was really chance Texas and/or any other state would secede, the economy & the dollar would collapse so fast (much faster than they already going to do anyhow) that the remaining US couldn’t do anything
Once those 1st of the month checks aren’t worth the gas it takes to drive to the bank to cash them, Liberals will first turn on each other. City after city will go “Katrina”.
You left out Tennessee. We are a conservative red state.