"Some Democrats have vowed to continue to investigate and pursue the obstruction of justice issues, in hopes of finally finding something they can legally use against him."

In other words Democrats will be to busy spending millions of tax payer's dollars to accomplish anything except trying to over throw an elected president who has already gone through two years of an investigation by a group of rabid Trump h**ers. If Democrats believed in God they would thank him for an over abundance of stupid people.

I can't say the following is applicable in the case of the Mueller Investigation, but it may well be...

The legal concept of 'Plausible Deniability':

'Plausible deniability is the ability of people (typically senior officials in a formal or informal chain of command) to deny knowledge of or responsibility for any damnable actions committed by others in an organizational hierarchy because of a lack of evidence that can confirm their participation, even if they were personally involved in or at least willfully ignorant of the actions. In the case that illegal or otherwise disreputable and unpopular activities become public, high-ranking officials may deny any awareness of such acts to insulate themselves and shift blame onto the agents who carried out the acts, as they are confident that their doubters will be unable to prove otherwise. The lack of evidence to the contrary ostensibly makes the denial plausible, that is, credible, although sometimes it merely makes it unactionable. The term typically implies forethought, such as intentionally setting up the conditions to plausibly avoid responsibility for one's (future) actions or knowledge. In some organizations, legal doctrines such as command responsibility exist to hold major parties responsible for the actions of subordinates involved in heinous acts and nullify any legal protection that their denial of involvement would carry.'

Read the report!!!! He did NOT obstruct an investigation. For example, there are some who say Trump pressured Comey to drop the investigation on Flynn. But what he did was ASK Comey if he could let it go. That hardly counts as pressuring. Trump had multiple opportunities to invoke executive privilege, yet he did NOT use his office to stop or interfere with the investigation. Complaining is NOT obstruction!!!! Even when the complaints are said angrily! He rued appointing Sessions and told Sessions so. But he did not tell him he must unrecuse himself and take over the investigation. Mueller never even had to subpoena White House records as Trump ordered his lawyers to turn them over to Mueller. Even those presidents who were beyond investigation and were actually under impeachment process have not willingly turned over records without subpoenas and d**gging their heels. Clinton certainly didn't cooperate with Ken Starr. And what the Clintons did definitely WAS obstruction! https://www.washingtonexaminer.com/washington-secrets/ken-starr-hillary-a-systematic-enabler-bill-clintons-affairs Nixon did everything BUT cooperate. Trump yelled and let those around him know how much he resented being investigated. That is NOT obstruction!!!! He repeatedly called the investigation a witch hunt. That is NOT obstruction!

So what exactly did he do which obstructed the investigation?

Read the report next time before you start making accusations why don't you?!?!

The legal definition of Obstruction of Justice is:
Definition
18 U.S.C. § 1503 defines "obstruction of justice" as an act that "corruptly or by threats or force, or by any threatening letter or communication, influences, obstructs, or impedes, or endeavors to influence, obstruct, or impede, the due administration of justice."

How that applies to the collusion investigation;
1) Trump did not corruptly threaten, force, send threatening letters or communications, or in any other way impede the investigation.
2) The due administration of justice implies a criminal investigation. i. e. a crime must be present.
3) He not only did nothing to impede the investigation, he cooperated fully with it.