Should Congress make some new rules to define what is impeachable and what is not? To prevent future political manipulation?

It's already spelled out in the Constitution . The problem lies in the Democrats desire to add impeachable offenses without any amendment .

Matthew....kindly stay off my page with your negativity. As for what I have in my bank that you think being able to sustain a mortgage and a whole lifestyle for a family for 18 months with no other income is tiny???? Lets have u match your portfolio against mine. Lets have u show me what you own, in your name? Little boy. Im waiting. My financial planner sees us im excellent condition. PS remember the average American lives paycheck to paycheck, so what I have is far beyond that and based on your answer, it tells me you have a low paying hourly job to which you do not understand money well enough to understand how great our savings is. Die

You should die of cancer, ugly.

Pretty sure the Constitution makes that rather clear. High crimes and misdemeanors. That's the elegance of the Constitution. It states the rules very clearly without a lot of fluff. 'The right of the people to keep and bare arms shall not be infringed.' Boom. There ya go. Couldn't be clearer. 'High crimes and misdemeanors' is just as clear, but it doesn't fit the left's narrative that pissing them off and obstructing their agenda is a criminal act.

Really, you can't make this stuff up.  

The founders left that purposely vague because, as Hamilton wrote, there would be know way for them to list all possible impeachable offences,

However I do think that there should be a better defined impeachment inquiry/impeachment trial process so all this craziness about being able to muck up the proceedings by making the process unfair can't be done

That would require changing the Constitution.    The amendment process is available and has been used.  Feel free to lobby for it.  You have that right under the Constitution.  Good luck, but I won't be joining you.

Hell no. The only thing a list like this would do is make it so crafty politicians could find a way to do something immoral that wasn't listed, or do something they're allowed to do in an immoral way.

The famous I Robot issue (Little lost robot)

A robot by action, or inaction, may not harm a human.

Remove "or inaction" and a robot can drop a 10 Ton weight knowing that the robot could stop the weight before it hit the human, then decide to take no action to prevent the human from being harmed from the falling weight.

You try to plan for every contingency, and someone will find a contingency you didn't think about.

Congress can't do that, you need to change the constitution. The democrats are trying to do that without the constitution. 

I don’t know.... you should ask Congress.

You mean amend the Constitution? Go for it cupcake.