Story highlights The emoluments clauses prohibits the President from receiving cash payments from foreign governments

To have standing to sue in federal court a plaintiff must show a concrete injury

(CNN) Three days into office, President Donald Trump was sued for allegedly violating the Constitution he took an oath to defend, but questions remain whether those behind the lawsuit have any standing to pursue a case.

The central legal argument lodged by the ethics accountability group on Monday was that the President has violated the foreign emoluments clause of the Constitution by accepting foreign payments through his business ventures.

While the initial complaint filed by the self-described non-partisan group Citizens for Responsibility and Ethics in Washington, raises a host of significant questions in somewhat uncharted legal territory, most experts have zoned in on a threshold issue that may stand in the way of the plaintiffs getting their day in court: standing. In order to sue in federal court, the Supreme Court has said it is not enough for you to show a mere interest in an issue, you must show your standing to sue by sufficiently articulating how you suffered a concrete and particularized injury.

Some legal experts questioned when the lawsuit was filed on Monday, even if the President is wrongfully accepting cash from foreign governments in violation of the emoluments clause, how is this ethics group -- which identifies itself as a independent ethics group that "works on behalf of the public to foster an ethical and accountable government and reduce the influence of money in politics" -- being harmed?

CREW's answer is that Trump's situation has forced it to "divert essential and limited sources" from its regular government watchdog role and "will essentially be forced into the role of litigating and educating the public regarding (Trump's) Foreign Emoluments Clause violations," if a court does not stop him, according to the complaint.

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