DW: Donald Trump has handed over the management of his businesses to a trust run by his sons. A Trump lawyer also said that the company would not engage in any new foreign deals during Trump's tenure and that new domestic deals would be vetted rigorously by a neutral ethics advisor. What's wrong with that approach?

Richard Painter: The president still owns the businesses, which means that all the money that is paid into the businesses is for the financial benefit of the president. And the money that comes from foreign governments, banks controlled by foreign governments or sovereign wealth funds is in violation of the United States Constitution. The Constitution specifically prohibits anyone who holds a position of trust with the United States government, including the president, from receiving economic benefits from foreign governments.

So that money from foreign governments and entities controlled by foreign governments is unconstitutional. Other money coming into the Trump business empire from private sources creates serious conflicts of interests. We are very concerned about the president having investments all over the world in places where there could be all sorts of trouble. That is not a good situation for the United States, and so we feel strongly that the president needs to divest ownership interest from his businesses.

You along with several other prominent lawyers and the watchdog group Citizens for Responsibility and Ethics (CREW) have sued President Trump under the so called Emoluments Clause, which bars high government officials from receiving gifts or money from a foreign state. You filed the suit a few days after the inauguration. What is the current state of the lawsuit?

This is one of dozens of lawsuits against the president in his official capacity because of the way in which the president has chosen to run his administration and conduct his business. Our lawsuit asks the judge to look at the foreign government payments coming into the Trump business empire, to look at the Constitution and decide what the president can and what he cannot keep under the Constitution. The suit has been filed, and the judge shall decide what the procedures going forward shall be and when decisions will be made. That is out of our control at this point.

While many legal experts agree that you may be right on the issue, they argue that you don't have the necessary "standing" to win the case, meaning that you are not personally hurt and affected by the case. How do you counter that?

The federal courts in the New York area where we filed the suit have been willing to give standing to organizations such as ours which had to substantially alter their work and their mission and have been affected by the unconstitutional conduct of government officials. There is case law in the second circuit court supporting our positions, and we hope that the courts do give standing. Ultimately, the Supreme Court may have to rule on that issue.

If the courts do not give standing to organizations such as ours, then the courts may end up not deciding this constitutional question at all, and the alternative would be for the House of Representatives in two or three years to convene a hearing and investigate and find out what foreign government money the president has received and then think about what action to take. The problem is that this is a very politicized process and will be for sure if the Democrats ever get control of the House of Representatives. It could result in impeachment of the president - a constitutional crisis - and this is something we believe can be avoided if the courts in a much more neutral manner are willing to give us standing and then decide what the president can keep and what he cannot.

Much has been made recently by opponents of the president about the 25th amendment as a possible way to remove Donald Trump from office without impeachment. The amendment allows the removal of a president who is deemed unable "to discharge the powers and duties of his office" temporarily by a majority vote of the vice president and cabinet, but ultimately requires a two-thirds vote in Congress. Do you consider this as a realistic option at all?

The 25th amendment is used to deal with a different situation - when the president is incapacitated, not when he is acting illegally. It is designed to deal with a president who is incapacitated due to the president's physical or mental health. At this point, all I would say is that President Trump should use better judgment in his public statements. That's where we are right now. I don't think the evidence is there at this point to say that the president is not physically or mentally capable of carrying out the duties of the president. But I do think he needs to be somewhat more careful and balanced in what he communicates to the public.

You served as the chief ethics lawyer for President George W. Bush. Can you briefly compare how President Bush dealt with ethics questions and how President Trump is handling them?

President Bush insisted that he as president set a good example for everyone working in the administration and that he set the right tone at the top. And President Bush, like every other president in recent memory, made absolutely sure that he had no financial conflicts of interests with his official duty. He followed the same rules as everyone in his administration. He did not say that he was somehow special because he was president. He never would have said that the president does not have a conflict of interest unless the president indeed had taken the steps that he took to make absolutely sure that there was no conflict of interest in fact. The president is not above the law, and President Bush was adamant about that point. That's one of many respects that President Bush was quite different.

He also felt very strongly that our country must welcome people of all religions and races. President Bush right after 9/11 made it very clear that the United States was not in a war with Islam and that we welcome Muslims to our country. We are certainly at war with extremism of any sort, and that is what the war on terror is about. President Bush would never have tolerated any effort to denigrate or discriminate against Muslims in the United States. He recognized that that was un-American and unconstitutional.

Richard Painter is a law professor at the University of Minnesota. From 2005 to 2007, he served as the chief White House ethics lawyer for President George W. Bush.

The interview was conducted by Michael Knigge.