The tree of liberty must be refreshed from time to time with the blood of patriots and tyrants
That quote can be used used to start "legitimate" wars, and those quoting will never engage personally.
Violence doesn't do any good. That stabbing was pointless and targeted (as usual) at the wrong person. And it will cause the following:
Higher security/ paranoia at future elections.
Condemning everyone who opposes the policy of "let them all in"!
The only real solution would be to elect new leaders, but given the constellation in any given Western "democracy" you'll likely end up with "more of the same".
Germany will have to spend a lot of money to accommodate the migrants, money that it doesn't have.
One option would be to make the rich and super-rich to actually pay their taxes in Germany, but what are the chances that's going to happen?
Angela Merkel already excluded the option of tax raises to cope with the migrant crisis. Which is basically her way of "introducing" that idea.
Helmut Kohl promised the exact same thing in 1990 after the re-unification, and guess what? Taxes went up and they actually invented a new tax (although they didn't call it a tax).
Anyone (migrant or not) without a required qualification or above a certain age can't get a decent job.
And sometimes even those with a good qualification can't get a decent job. So what will happen with migrants who don't speak the language and/or have any useful qualifications? They will a liability to the social welfare systems and those will eventually collapse in the not so distant future.
The new estimated number of migrants for this year alone has been corrected to 1,5 million people. That is a major German city like Hamburg. The communities across Germany seriously struggle to cope with the migrants, to provide housing, food and warm clothing.
And despite all this the German chancellor sticks to her "Wir schaffen das!".
Turkey (with an upcoming general election in that country) is getting way too much leverage now. They not only want money, they want into the EU.