[Paleo Conservative]

Paxton ran unopposed in the May 29 primary.

No he didn't! And the primary was on March 4 not May 29. The runoff was on May 27, and by definition there is an opponent in a runoff election.

Office of the Secretary of State

Race Summary Report

2014 Republican Party Primary Election

3/4/2014

Attorney General
Dan Branch REP 428,325 33.46%
Ken Paxton REP 569,034 44.45%
Barry Smitherman REP 282,701 22.08%
-----------
Race Total 1,280,060

Office of the Secretary of State

Race Summary Report

2014 Republican Party Primary Runoff

5/27/2014

----------------------------------------
Attorney General
Dan Branch REP 269,098 36.59%
Ken Paxton REP 466,407 63.41%
-----------
Race Total 735,505

[Cboldt]

That's what I get for cut and paste without reading. See Ken Paxton - Ballotpedia for the source of my error, where the date refers to the 2012 state senate election.

To the question of "why didn't any of his opponents use this?", here's another cut and paste ...

Republican voters knew about Paxton's problems during the 2014 primary when fellow conservative Barry Smitherman used it in an attack ad on television.

Unsigned Warrants Could Delay Paxton Surrender KCENTV.com -