How can you make a public policy maker adopt your public policy solution?

Make it the best solution for them at the time. For example if you want to outlaw guns wait until something happens you can blame on guns. Then whip up the people with grief and outrage. Then tell the public policy maker that adopting your solution will calm the people and advance the makers political career.

War is also a great way to get policy makers to adopt policies that would otherwise never be acceptable. A couple decades ago most in the Western World would not accept the current levels of government monitoring and control but with the fear from the war on terror Western Governments now have policies that would have been seen as extreme and non-democratic not long ago.

Another way is to get funding from the government, then use that money to influence government to give you more money. Eventually they will be giving you so much money that they have to adopt your policies to justify the money they have given you.

Yet another is to get the people to demand the public policy maker adopt your policies. History has shown this is best done by suggesting there is some very bad evil or repercussion as a result of their evil and immoral ways. For example tell them that their sexual sins are causing Comets to be seen in the sky, which always means bad things will happen BUT if they do what you say, like pay indulgences, the comets will stay away.

So get the policy maker to see advantage for them, or get people fearful enough to advance your cause for you.