Chris Cillizza recently wrote an article in cnn.com where he laid out 5 reasons why Nancy Pelosi doesn't want to impeach Trump. While I am glad to see someone pointing out the various serious problems with impeachment that those clamoring for it seem to ignore, there is one item where he made a glaring mistake and that is item 2 which claims Trump will never be impeached anyway making the House impeaching Trump "purely a symbolic move, with no actual teeth."
It's actually far worse than that.
First, he is making the common mistake that many out there are making which is conflating impeachment, meaning the act of charging or accusing the president (see here or here) with the act of convicting and removing the president from office. When he says the president will never be impeached. That is simply not true. If the House votes to impeach he will definitely be formally accused and he will definitely be put on trial in the Senate. I don't believe there is anything Mitch McConnell or the White House can do to stop that.
The problem is not that he won't be impeached. It's that he will be acquitted. To convict him would require all 48 Democratic Senators to vote to convict and 18 Republican Senators to vote to convict, essentially throwing away their political careers and condemning themselves to a lifetime of vilification by the right. The odds of your winning the mega millions lottery are far better than this occurring. Even getting one Republican to vote to convict would be a minor miracle and only likely from one who was planning on retiring anyway. The current Republican party is not based on morality or ethics or any high minded principles,but rather on loyalty. It is the glue that binds them and thus is held above everything else. The only way they would even consider voting to convict is if Trump suddenly became highly toxic to the Republican party, something which there is currently no reason to believe will occur any time soon.
This acquittal would be far more damaging to the Democrat's position than people seem to realize. You see, by impeaching the president, the House is basically legitimizing the impeachment process. Once it has done so, it can hardly claim it illegitimate when the Senate acquits Trump. A bulwark of the Democratic position has been that they support and defend the rule of law. Well a trial in the Senate followed by exoneration of the president would be just that so Democrats would have to accept the verdict. To do otherwise is to basically make a mockery of the rule of law and behave just like Trump, claiming the system is legitimate when agrees with its conclusions and illegitimate when he does not. The whole moral high ground would be lost if Democrats started to act this way.
That means no more investigation of issues that were "settled" in the impeachment process. No more claiming that Trump is guilty of obstruction. Any such action would make a mockery of the rule of law. Unlike in the current situation, following his acquittal in the Senate, Trump could legitimately claim he had been found not guilty just as Clinton did when his impeachment effort failed. Democrats can hardly claim that Trump declaring himself not guilty is illegitimate but Clinton doing so was legitimate.
So what is the right approach ? The Democrats must make it clear that they do not see the impeachment process as being any longer legitimate in the 21st century To be legitimate one would expect the thinking in the Senate to largely parallel that in the courts. A huge deviation like we have could only be justified if there were some overarching argument for it and there is none. We know this thanks to the wonders of video. The very same people like Lindsay Graham who justified his actions in the impeachment of Clinton on the basis of his clear obstruction of justice now pretend like that's no longer relevant. This is clearly not a measured legal argument but pure unadulterated partisanship. People like Lindsay Graham allowing partisanship to rule their thinking has de legitimized the whole impeachment process and the evidence is there in black and white.
So if impeachment is no longer a legitimate system for holding people like Trump accountable what should Democrats do ? Well there are two other areas which are much more likely to hold him accountable: the ballot box and the courts. When Trump, hopefully, loses in 2020, the Democratic administration should make it a top priority to refer Trump for criminal indictment. They should find a suitably non-partisan actor within the justice department to do so and then let the courts decide. To do otherwise is to basically flout the rule of law and thus give up the moral high ground. At any rate, it is highly likely he would be convicted given the significant evidence against him. He could also potentially be charged with obstruction over his other attempts to shield himself from investigation by the Congress. I believe this is the only way that Trump can truly be brought to justice.