Challenge every Court's jurisdiction.
Challenge every judge's standing.
Challenge the crossed i's and dotted t's of the plantiffs' cases.
Appeal every decision to the US Supreme Court.
Fight lawfare with lawfare. Have the IRS audit non-profit NGO's, Institutes, and Foundations. Have the Treasury Department forensically determine the source of truth for the money that went to them. Have the GSA audit NGO's, Institutes, and Foundations that received Federal funds. Have the Office of Management and Budget audit the Federal agencies that disbursed money for illegal border crossers.
Send in the lawyers. Send in the auditors. Send in the accountants. Let's (figuratively) rumble.