Beyond the fact that you are stupid for beleiving every "source with knowledge" bulshit story we've heard despite 3 years of it never panning out there is the obvious. If Trump , or anyone else for that matter, conspired to get a witness to lie to Congress, that would be illegal, but it wouldn't be "obstruction of justice"
And of course, riddle me this, why have only 7 people been charged with a crime in relation to lying to Congress since WWII, when in fact dozens of people have been caught lying to Congress in just the last year.
Here's the people off the top of my head who most certainly lied to Congress in the last few years, and haven't faced charges yet.
James Comey
Eric Holder
Barrack Obama
Hillary Clinton
Mark Zuckerburg
Andrew McCabe
Sundar Pichai
Peter Strozk
Sally Yates
Loretta Lynch
Susan Rice
James Clapper
That's just right off the top of my head people who have lied to Congress, we all KNOW they lied and no charges.
Hell in the case of James Clapper, he actually orchestrated the NSA breaking into the server of the House Intelligence Oversight Committee and then lied about it when caught and NOTHING was done about it. Can you seriously think of ANYTHING more egregious than a government agency hacking into the computer system of the Congressional oversight committee charged with making sure they follow the rules?