As a Buddhist, to be engaged in mainstream politics is very difficult because we cannot know the real truth of politics, unless we are absolutely certain.
For example, I have heard some of the most famous Western Theravada monks & the Dalai Lamai speak about 9/11 as though Islam really did it & provide ideas that justify war.
Since there was no real evidence Islam did 9/11 & since the American wars after 9/11 were unrelated to the alleged (Saudi Arabian Wahhabi) terrorists, how can a Buddhist speak truthfully in any way that supports war & killing with a unknown & unproven view?
Similarly, these same Western Theravada monks recently were supporting presidential candidates who were engaged in wars & murder because they believed some other policies of these candidates were better than the other.
Therefore, we have Buddhist monks & nuns encouraging their supporters to vote for political parties that engage in unjustified wars & killings.
It follows, unless you are truly certain who you support politically will not engage in any harm, how can you, as a Buddhist, support mainstream politics?
How can you get passionate about opposing Donald Trump or Viktor Orbán when the alternative is really no better, from a Dhammic point of view. Basically all of the major politicians, when examined closely, are violating the Buddhist moral precepts.
For example, the only Australian politician I listen to (occasionally) was originally an intelligence officer 'whistle blower' about the weapons of mass destruction before the Iraq War. Naturally, he was proven to be right. I recently phoned his office about the Syrian gas attack &, as a result, he was the only Australian politician to make an honest & moral statement about it, namely, there was no evidence that is was a deliberate chemical attack.
What I am saying here is if you get involved in truly moral politics, you will have very little support & feel quite powerless. When you realize how powerless you are to affect real change, the 'passion' diminishes greatly. Although you may occasionally try to do something, you realise there is little you can do to affect real change when the majority of people are still supporting the major political parties.
Buddhism explains six realms of existence: (i) human; (ii) benevolent godly (deva); (iii) violent godly (asura); (iv) animal; (v) ghost; & (vi) hell.
Most politicians & rulers throughout history have been violent gods (asuras), which is why they resort to military violence to achieve their ends.
In other words, in my opinion, they are not regular human beings like you and me. Their disposition is inherently evil, psychopathic & animalistic.
The Buddha described this non-human animalistic behaviour as follows:
Here, bhikkhus, there is no conduct guided by the Dhamma, no righteous conduct, no wholesome activity, no meritorious activity. Here there prevails mutual devouring, the devouring of the weak.
SN 56.47
In this respect, the Buddha taught to view evil as evil, for what it really is, in a way that leads to disenchantment & dispassion towards the world:
'See evil as evil.' This is the first Dhamma discourse.
'Having seen evil as evil, become disenchanted there, dispassionate there, released.' This is the second Dhamma discourse.
These are the two Dhamma discourses that the Tathagata — worthy & rightly self-awakened — has given in sequence."
Iti 2.12
Those who imagine evil where there is none, and do not see evil where it is — upholding false views, they go to states of woe.
Those who discern the wrong as wrong and the right as right — upholding right views, they go to realms of bliss.
Nirayavagga
While we can try, the Buddha did not really place great hope in the world. Instead, he taught the world is evolving following Dependent Origination, i.e., evolving with ignorance & craving.
If we examine the history of the world, for thousands of years, it is just war after war. When there is a particularly vicious & destructive war, such as WW2, the people take a rest from war. But then soon enough, they start again. Has there really been any change?
The USA has spent $5 trillion on a war on terror. However, there is more terrorism today than there was when this war began. Yet how many people question this war & what it is really about?
According to the scriptures, the Buddha taught the majority of the people in the world are spiritually blind. If you have this right view, you will give up politics because you will realise you cannot really change anything politically (apart from yourself).
174. Blind is the world; here only a few possess insight. Only a few, like birds escaping from the net, go to realms of bliss.
171. Come! Behold this world, which is like a decorated royal chariot. Here fools flounder, but the wise have no attachment to it.
170. One who looks upon the world as a bubble and a mirage, him the King of Death sees not.
58. Upon a heap of rubbish in the road-side ditch blooms a lotus, fragrant and pleasing.
59. Even so, on the rubbish heap of blinded mortals the disciple of the Supremely Enlightened One shines resplendent in wisdom.
Dhammapada