The thing about impeachment is you have to take it seriously.

[Kablooie]

You have to have enough evidence and make a strong enough case that you believe might turn some Republicans.

To impeach with the full expectation that no Republicans would join would be an ineffective gesture.

[SunSeeker]

1. No, impeaching without Republicans would not be an "ineffective measure."

We are the majority in the House. We can impeach Trump in the House without a single Republican vote. And before that vote, in the impeachment investigation hearings, we can showcase the grave crimes Trump has committed to our country. An impeachment hearing is taken much more seriously and garners much more media attention than a regular hearing, and thus will educate more Americans about Trump's crimes.

Regular oversight hearings do not give authority to Congress to obtain grand jury info. We need Mueller's grand jury info as evidence, but Barr says he cannot turn it over due to grand jury secrecy and he is right. Only formal impeachment proceedings, not regular House proceedings, are entitled to receive grand jury info:

Per the Washington Post:

Significantly, the appeals court decision several days ago reaffirmed that exception. All three judges agreed that an impeachment inquiry falls within the “exception for judicial proceedings” and “coheres” with other rulings about the proper scope of grand jury secrecy.  

https://www.washingtonpost.com/opinions/the-full-mueller-report-could-be-released--if-the-house-opens-impeachment-hearings/2019/04/08/e47fff42-5a14-11e9-a00e-050dc7b82693_story.html  

Trump welcomed a Russian attack on our country in order to gain office, then obstructed our Justice Department, sacking an AG and an FBI Director, in order to stop the investigation into that attack. This is horrifically worse than Watergate. We must expose this behavior in the context of a formal impeachment investigation because only that properly shows the seriousness of the conduct.

You do an oversight hearing on a cabinet secretary spending $40k of taxpayer money on a dining set for his office. You do an impeachment investigation hearing on a President who a Special Counsel found welcomed a Russian attack hacking our democracy, them tried to repeatedly to stop the investigation of that attack.

We must be on record as impeaching a president who committed these grave, treasonous crimes. He will go down in history as only the 3rd President to be impeached, even if the GOP house votes not to remove him.

That will have an effect. It will damage Trump while energizing our base going into 2020.

And if we don't move to impeach, it will depress our base turnout, make us took like we won't stand up for the rule of law, and Trump will claim he has committed no wrongs, since we never moved to impeach.