Mueller this big
For those hoping the conclusion of the Russia probe will finally help put the controversial 2016 election behind us, prepare to be disappointed. Nobody beyond special counsel Robert Mueller's team knows exactly what evidence has been found that the Trump campaign colluded with Russia to win the 2016 election. We may learn there was no indication that President Trump personally did anything illegal. Or Mueller may lay out rock solid proof of a criminal conspiracy or other violations that causes a chain reaction leading to the downfall of the Trump administration.

However, based on what we know to date, the most likely outcome will be something frustratingly in between. Barring a major deviation from Justice Department policy, Trump will not be indicted. The unique role of the president calls for a unique remedy to punish wrongdoing: impeachment under Article II of the Constitution. This would require a majority in the House to impeach and a two-thirds majority in the Senate to convict. Upon conviction, the sole punishment is removal from office.

As a result, impeachment is a political remedy rather than a legal one, with members of Congress closely watching public opinion polls as they decide the fate of a sitting president. So as a practical matter, any evidence will effectively need to meet the highly subjective standard of whether it merits removing a president from office, which is something that has never happened in American history.

We have only to look to the 1998 impeachment of former President Clinton to see how this has played out in the past. Clinton was impeached for lying to a federal grand jury and prompting witnesses to do the same. Following his trial in the Senate every single Democrat and several Republicans voted against conviction. Did they do so because they thought he was not guilty? No. It was because they decided that lying about sex did not justify removal of a president twice elected.

The issue for Trump will not be whether he engaged in conduct that could theoretically be prosecuted. The real question is what it will take to turn public opinion against him and prompt a majority of the House and two-thirds of the Senate, including some Republicans, to remove him.

Let us assume the worst about the 2016 Trump Tower meeting. Say members of the Trump campaign met with an attorney they knew represented Moscow and who promised to provide opposition research on Hillary Clinton. Let us also assume that candidate Trump learned of the meeting either in advance or after the fact, and later authored the public statement that falsely described its purpose. Yet, barring some evidence that has not yet come to light, there is nothing to indicate that anything of value was actually given to the Trump campaign by Russia as a result.

So we potentially have a case of "attempted collusion," coupled with a ham-handed attempt to lie about it to the public. Is that illegal? Potentially. Could federal prosecutors build a campaign finance or other criminal case on these facts? Most likely. Will two-thirds of the Senate convict and remove President Trump on this basis alone? Absolutely not.

What about Mueller investigating potential obstruction of justice? We know he is looking at whether Trump pressured former FBI Director James Comey to end the investigation of Michael Flynn, and whether the president's subsequent firing of Comey was meant to obstruct the FBI's Russia investigation. We have seen reports that Mueller is investigating the fact Trump has considered firing Attorney General Jeff Sessions, Deputy Attorney General Rod Rosenstein, and the special counsel himself.

Yet, the Flynn prosecution continued unmolested. The FBI's Russia investigation moved forward despite Comey's removal. Sessions, Rosenstein, nor Mueller were terminated. If Mueller brings forth proof of a quid pro quo between the Trump campaign and the Russian government, or evidence of document destruction, lying, witness tampering, or other conduct clearly intended to prevent investigators from getting to the truth, the president's public and congressional support will collapse.

But if the best Mueller comes up with is circumstantial evidence of crimes that would require creative legal theories to prosecute, Trump voters will not be swayed. Will two-thirds of the Senate convict a president for "attempted obstruction" on a theory of corrupt intent based on comments he made to Lester Holt and the Russian foreign minister? Not likely.

This is not to say the president will escape without consequence. The Trump Tower meeting demonstrated horrendous judgment and a willingness to violate the law. Paul Manafort should not have been allowed anywhere near a presidential campaign. The same goes for Flynn, whose baggage made him clearly unfit for a senior White House position. All of this and more will likely be described in scathing detail by Mueller and will reflect poorly on the president, his family, and those he associates with.

Back in 2016, Republicans hoped that Hillary Clinton would be taken down by the FBI's investigation into her email server. Trump's critics should not make the same mistake. It is certainly possible that Mueller is sitting on blockbuster evidence that will lead to the end of this administration. However, based on what we know so far that is not likely. Do not hold out hope for a legal solution to the Russia matter. This is a political issue that will require a political resolution the hard way - at the ballot box.

Joseph Moreno is a former federal national security prosecutor with the U.S. Department of Justice. He is now a white collar litigation partner at Cadwalader, Wickersham & Taft. Follow him on Twitter at @JosephMoreno.