Dan Wallach, who is an expert on electronic voting machines and their security, sums it up succinctly:
Texas’ [direct-recording electronic (DRE) voting machines] are simply vulnerable to and undefended against attacks.
That’s the last sentence of a long post about his recent testimony (PDF) to the House Elections Committee and the response from the electronic voting machine trade organization, which as you may imagine did not agree with him. Read it for yourself and see what you think.