IN THE UNITED STATES DISTRICT COURT

FOR THE EASTERN DISTRICT OF TEXAS

MARSHALL DIVISION

HEADWATER RESEARCH LLC,

Plaintiff,

vs.

AT&T INC., AT&T SERVICES, INC., AT&T 

MOBILITY, LLC AND AT&T CORP.,

Defendants.

Civil Action No. 2:23-cv-00397 

LEAD CASE

JURY TRIAL

HEADWATER RESEARCH LLC,

Civil Action No. 2:23-cv-00398

Plaintiff,

vs.

JURY TRIAL

AT&T INC., AT&T SERVICES, INC., AT&T

MOBILITY, LLC AND AT&T CORP.,

Defendants.

AT&T’S RESPONSE TO PLAINTIFF’S 

NOTICE OF SUPPLEMENTAL AUTHORITY (DKT. NO. 57) 

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1

Defendants AT&T Services, Inc., AT&T Mobility, LLC and AT&T Corp. (collectively, 

“AT&T”) submit this brief response to Plaintiff’s Notice of Supplemental Authority regarding the 

pending Motion to Disqualify McKool Smith. 

Plaintiffs’ notice identifies the Court’s recent order, Headwater Research LLC v. Samsung 

Electronics Co. Ltd., No. 22-CV-00422-JRG-RSP, Dkt. 198 to argue that the Motion to Disqualify 

should be granted. While that order does address the degree to which Headwater and Interdigital 

may have shared a common legal interest, it is distinguishable for several key reasons. First, that 

order addressed a motion to compel, not a motion to disqualify. The legal standards, burden, and 

practical ramifications for these two motions are markedly distinct. In the Fifth Circuit, 

disqualification is “an extreme remedy that will not be imposed lightly.” Duncan v. Merrill Lynch 

Pierce, Fenner & Smith, 646 F.2d 1020, 1025 n. 6 (5th Cir. 1981). Trial courts must consider 

disqualification motions “with meticulous deference to the litigant’s rights.” F.D.I.C. v. U.S. Fire 

Ins. Co., 50 F.3d 1304, 1314 (5th Cir. 1995). Courts in the Eastern District of Texas subject 

motions to disqualify to “an exacting standard both to protect a party’s right to counsel of choice 

as well as to discourage the use of such as a dilatory trial tactic.” Biote Med., LLC v. Jacobsen, 

2020 WL 2813201, at *2 (E.D. Tex. May 29, 2020).

Second, the order suggests that rather than challenging the existence of a common interest 

privilege, Samsung errantly conceded that there was at least a “one-way common interest”). Id. Of 

course, neither Samsung nor its counsel had access to the various sealed declarations filed in this 

case that demonstrate that Headwater and Interdigital were in fact counterparties in negotiations 

and were not contemplating any sort of joint litigation. See, e.g., Dkt. No. 47-5 ¶¶ 5, 6; Dkt. No. 

47-4 ¶ 3. In contrast, AT&T has directly challenged the existence of any common interest between

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the parties in view of controlling Fifth Circuit authority not analyzed in the Court’s order. See Dkt. 

No. 47, at 9-12 (citing In re Sata Fe Intern. Corp., 272 F.3d 705 (5th Cir. 2001)). 

Third, even if the Court were to conclude that some degree of common interest privilege 

applied to some communications between Headwater and Interdigital, the Motion to Disqualify 

should still be denied because Headwater has failed to demonstrate that the purportedly privileged 

communications were substantially related to its assertion against AT&T. Nor could it since even 

Headwater concedes that it never even discussed suing AT&T with Interdigital. See Dkt. No. 51, 

at 5.

In sum, the Court’s recent order in the Samsung case on a different evidentiary record and 

legal standard is not controlling—much less dispositive—of the pending Motion to Disqualify, 

which should be denied for the reasons set forth in AT&T’s prior briefs. Dkt. Nos. 47, 51.

Case 2:23-cv-00397-JRG-RSP Document 62 Filed 06/11/24 Page 3 of 5 PageID #: 1137
Dated: June 11, 2024. MCKOOL SMITH, P.C.

/s/ Nicholas Mathews

Nicholas Mathews

Texas State Bar No. 24085457 

nmathews@McKoolSmith.com 

Erik Fountain 

efountain@McKoolSmith.com 

Alexander J. Chern

Texas State Bar No. 24109718 

achern@McKoolSmith.com 

Clare Churchman

Texas State Bar No. 24132041 

cchurchman@mckoolsmith.com 

MCKOOL SMITH, P.C.

300 Crescent Court Suite 1200 

Dallas, TX 75201 

Telephone: (214) 978-4000 

Telecopier: (214) 978-4044 

Kevin P. Hess 

Texas State Bar No. 24087717 

khess@McKoolSmith.com 

MCKOOL SMITH, P.C.

303 Colorado Street, Suite 2100 

Austin, TX 78701 

Telephone: (512) 692-8749 

Telecopier: (512) 692-8744 

Deron R. Dacus 

State Bar No. 00790553 

ddacus@dacusfirm.com 

THE DACUS FIRM, PC

821 ESE Loop 323, Suite 430 

Tyler, TX 75701 

Telephone: (903)705-1117 

Facsimile: (903) 581-2543 

ATTORNEYS FOR AT&T CORP., 

AT&T INC., AT&T MOBILITY LLC, 

AND AT&T SERVICES INC.

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CERTIFICATE OF SERVICE

I hereby certify that a true and correct copy of the above and foregoing document has been 

served on all counsel of record via the Court’s ECF system on June 11, 2024. 

/s/ Nicholas Mathews

Nicholas Mathews

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