Seek out common underlying values
Oftentimes, disagreements in politics are really matters of common values with two opposed solutions. Consider this argument:
A: The poor people in our community need money through welfare to help make ends meet.
B: That will just make them lazy and keep them in poverty. We should limit the amount of welfare to encourage them to get well-paying jobs.
What isn’t being talked about here is that both A and B have a shared underlying value: they both want to help the poor. The disagreement is over the most effective way to do that. If A and B were to focus on their shared goal, then would be able to spend more time agreeing and less time arguing.
Ask for reasons why; don’t assume
I’ve seen this a lot in the United States after the very heated 2016 presidential election. Here is a bad conversation:
A: I voted for Trump.
B: How could you vote for that racist, bigoted idiot?!
A: Well, who did you vote for?
B: I voted for Hillary.
A: How could you vote for that morally bankrupt, elitist candidate?!
A better way is to always ask for reasons and not assume. They may have very good reasons that may surprise you.
A: I voted for Trump.
B: What were your reasons?
A: My family are all blue collar workers. I feel strongly about the difficulties they have in being able to put food on the table. While Trump is far from an ideal candidate, I think he is their best shot for making ends meet. Who did you vote for and why?
B: I voted for Hillary. I feel strongly about the causes of minorities, and especially immigrants, like that of the friends I grew up with. I think that they will have the best chance of a happy, stable life if Hillary is elected.
Note that A didn’t vote for Trump because he was bigoted and B didn’t vote for Hillary because she was morally bankrupt or elitist. They both had other reasons that were far different than the reasons the other assumed. In fact, they may find understanding on that B sympathizes with the financial difficulties of A’s family and A sympathizes with the social difficulties of B’s lifelong friends.
Invite them to share what they don’t like about their candidate or cause, and do the same
This goes back to the stereotypes and assumptions you have about negative traits. You may find that you are in agreement about a number of things.
B: You’re a Trump supporter. What don’t you like about him?
A: He’s bigoted, especially towards immigrants. I hate that!
B: Really?! I was afraid that you were supportive of him restricting rights to people like my friends.
A: You supported Hillary. What don’t you like about her?
B: I think she shows too little concern over the difficulties of rural, blue collar workers.
A: Really?! I was afraid you were deaf to the concerns about people like my family!
To both A and B’s surprise, the other wasn’t in support of their candidate because of their negative traits, but in fact they both despised the two candidates for the same reasons and discovered shared common values, despite ultimately picking different candidates.
This can also apply for causes too.
A: I am supportive of anti-abortion efforts, but I don't like how organizations promoting that provide little financial support to poor women who choose to keep their child.
B: I am supportive of LGBT rights, but I don't like how organizations advocating that can often be hostile to others who don't fully support their views yet are still aid the cause (such as religious groups that do not support homosexuality, yet host homeless shelters that are lifesaving to LGBT homeless youth).
In this case, both A and B have found common ground in wanting to find ways to better serve the disenfranchised in their society in order to solve the underlying problems affecting the causes they are passionate about.
Note that this is not an opportunity to find weaknesses in their arguments. The absolute wrong thing thing to say would be "well, if you don't like X about your cause/candidate, how can you possibly support them?" Doing that violates the trust and openness that you have created and will lead to closing down and hurt feelings.
Don’t go on the offensive
So now you’ve identified the other’s reasons and disproved the stereotypes and fears you had by taking the time to understand their point of view (You did do that right? It’s a critical step!) Now it’s time to convince the other person that your point of view is more valid, right?
Wrong! Going on the offensive is likely to cause more hurt feelings and not change others minds.
A: I feel strongly about anti-abortion efforts.
B: I feel strongly about LGBT rights.
A and B: My cause is more important!
It’s very unlikely that either side will change their mind, even if they agree that both causes are important. Going on the offensive will only cause hurt feelings. Again, seeking to understand each other is the better solution.
B: Why do you feel so strongly about anti-abortion causes?
A: It’s because […] Why do you feel strongly about LGBT rights?
B: It’s because […]
A: While I still think that anti-abortion causes are more important, I’m glad to better understand your position.
B: Same for me.
Here’s a good rule of thumb: if you don’t think there is a chance that you will change your point of view, don’t expect the other to do it.
Also, consider that the other person may change their view over time, rather than instantly. Multiple sessions of constructive, sympathetic conversation are more likely to be successful than a one time heated debate.
Your goal is to have a relationship, not to win political debates
Also known as: you’re in a relationship with this person, not a candidate or cause.
The other person is more than just the sum of their political values. You started the relationship for reasons aside from politics. Maybe it was shared interests or other shared values. Are these more important to you than which candidate they checked on the voting ballot?
To give a bit from my own background, my parents are diametrically opposed politically. They are of opposite parties on the political spectrum and disagree on a number of issues. But they’ve just celebrated 33 years of marriage thanks to focusing on all the other things they have in common: shared values unrelated to politics (such as their religious faith), shared interests, and a genuine love for each other as a person. They married each other, not Trump or Hillary.
Do they have disagreements? Sometimes. But ultimately they know that their goal is to be in a relationship with each other and not to win political debates.
For them, that also means not talking politics often (they had a rule to never have political debates in front of kids). But they firmly believe that their marriage is more important than having those debates. And that is an example I seek to follow.
Further Resources: Better Angels
The techniques listed above are used extensively by Better Angels, an organization built around bridging the political divide in the United States. From their website:
Launched in 2016, Better Angels is a bipartisan citizen’s movement to unify our divided nation. By bringing red [right-leaning, commonly Republican] and blue [left-leaning, commonly Democrat] Americans together into a working alliance, we’re building new ways to talk to one another, participate together in public life, and influence the direction of the nation.
The organization has articles, podcast, videos, and even live sessions aimed at creating understanding between those on opposing ends of the political spectrum. In other words, they resolve the exact same conflicts that you are trying to resolve, but on a much larger scale.
Even if you aren't in the United States, the resources that Better Angels provides can teach you about useful techniques and advice that can help you solve the conflicts between your girlfriend and any others you find at odds with politically.