Pelosi’s decision is political, and thus, is consistent with the political nature of impeachment. But Pelosi’s standard for impeachment--evidence so compelling that it overrides Republican opposition to impeachment--ignores the evidence already accumulated against Trump. Evidence against Trump of conspiracy, obstruction of justice, and violation of the emoluments clause of the Constitution already exists. It is unlikely that Republicans will ever vote to remove trump. Thus, Pelosi seems to be taking impeachment off the table because Republicans in the Senate will not vote to remove Trump.
If Trump cannot be removed because of Republican opposition, then the benefits and costs of impeachment without removing Trump from the Presidency should be weighed. One clear advantage is to hold Trump accountable for his actions. The notion that only voters should remove Trump not only flies in the face of the Constitution, which requires the removal of a President who commits high crimes and misdemeanors. Moreover, hoping that Trump is not re-elected would put him in the same category as George H.W. Bush and Jimmy Carter. Neither those one-term Presidents nor Trump deserves that!
According to some Democrats, one cost of impeaching Trump is that it would derail the Democratic legislative agenda. That is undoubtedly true. But it should be noted that Democratic legislation, once it passes the House, will die in the Senate. Republicans in the Senate will not pass Democratic bills, and Trump will not sign them. The Democratic bill will suffer the same fate as an impeachment.
The second cost of impeachment, according to some Democrats, is that it will imperil the chances of Democrats keeping the majority in the House, winning the majority in the Senate, and winning the Presidency. All this potential winning, however, may never occur. Voters may wonder why, if Trump was guilty of so many crimes, you didn’t impeach him. The normalcy of not impeaching Trump may make it possible for him to capitalize on his incumbency and win a second term.
Democrats hope that oversight investigations in the House can substitute for an impeachment hearing. But these hearings will, by definition, present an incoherent and piecemeal story. The advantage of a Congressional impeachment hearing is that it will show a coherent story that will shape public opinion. Also, it is not clear how fast these investigations will move. Certainly, Trump will not cooperate and fight as many court battles as he can. The Congressional oversight investigations will be stalled.
Above all the 2020 election is fast approaching. At some point, the House members will need to move into campaign mode. And that will not include investigations.