The most important argument in favor of forcing U.S. district judge Gonzalo Curiel to recuse himself from the Trump University lawsuits was published today by the Conservative Treehouse.

The Treehouse linked to a copy of Judge Curiel's "United States Senate: Committee on the Judiciary – Questionnaire for Judicial Nominees" in which, on page four of his response, Judge Curiel states that he is a "Life-time Member" of the "Hispanic National Bar Association [HNBA]."

The HNBA made public a press release in July 2015 that called for the following actions against Donald Trump and his enterprises:

The HNBA calls for a boycott of all of Trump business ventures, including golf courses, hotels, and restaurants. We salute NBC/Universal, Univision and Macy's for ending their association with Trump, and we join them in standing up against bigotry and racist rhetoric. Other businesses and corporations should follow the lead of NBC/Universal, Univision and Macy's and take similar actions against Donald Trump's business interests.

A case can be made that no sitting judge should be aligned with any such activist organization in general, but for a judge to preside over a case involving a defendant's business whereby said judge is also a lifetime member of an organization that very recently made public calls for a general boycott of the defendant's businesses is an undeniable stain on the purported impartiality of the judiciary.

In this sense, the case has similarities to the well known judgment of In Re Pinochet by the U.K. House of Lords from 1998/1999.  Here, Lord Browne-Wilkinson laid out the universal principles of apparent bias that can also be applied to the situation of Judge Curiel presiding over any litigation involving Trump:

The fundamental principle is that a man may not be a judge in his own cause. This principle, as developed by the courts, has two very similar but not identical implications. First it may be applied literally: if a judge is in fact a party to the litigation or has a financial or proprietary interest in its outcome then he is indeed sitting as a judge in his own cause. In that case, the mere fact that he is a party to the action or has a financial or proprietary interest in its outcome is sufficient to cause his automatic disqualification. The second application of the principle is where a judge is not a party to the suit and does not have a financial interest in its outcome, but in some other way his conduct or behaviour may give rise to a suspicion that he is not impartial, for example because of his friendship with a party. This second type of case is not strictly speaking an application of the principle that a man must not be judge in his own cause, since the judge will not normally be himself benefiting, but providing a benefit for another by failing to be impartial.

By being a lifetime member of the HNBA, and via the HNBA's press release making critical statements specifically against Trump while also calling for a general boycott of Trump's businesses, there are reasonable concerns that Judge Curiel is acting as "a judge in his own cause" (i.e., the "cause" of harming Trump's business interests).  At the very least, Judge Curiel's "conduct or behaviour may give rise to a suspicion that he is not impartial ... because of his friendship with a party" such as the HNBA, which has called for open economic warfare against Trump.

To allow this case to go forward with Judge Curiel presiding is highly likely to bring the administration of justice into disrepute.  Trump isn't the one who should be embarrassed or chastised.  In fact, it is Judge Curiel who bears the shame for not bringing these facts to the public's attention and recusing himself.