Oh, please. Global warming, nutrionists, environmental issues in general (on both sides, not just government funded), activist medical scientists, if you don't already realize this you'll probably explain away anything I would produce. This is endemic, not isolated.
It doesn't count that it's really important!!, like the global warming scientists. It's still scientists in politics, not merely saying what is happening but what we should do about it and when. It doesn't count that you like what the political scientists are saying, it's still scientists in politics.
This is insincere. Scientists have been in policy since the beginning of time. Some of the greatest scientists in early US history were literally politicians. But beyond that policy makers routinely have gone to scientists for recommendations. From where to find fish and gold, to which foods to eat to prevent illness and disease. These predate the US as a country.
The big problem is that when science goes head to head with the "politics" of the day then there are problems. Galileo encountered this, as did even Darwin (he elected to withhold publication to avoid many problems). The end result in the short-term is the scientist is ostracized ... the long-term vindicated.
Now maybe you're asking scientists to do the same today. Don't publish papers or offer recommendations if it will ruffle feathers. I'm sure many scientists do this, but frankly I don't think this is a satisfactory answer.
Oh, so you don't have any concrete examples. Try to find some, the experience might teach you something.
Edit: on re-reading, that sounded way snarkier than I wanted. What I mean is, actually do the exercise of trying to find quotes of scientists playing politics. It's not as easy as you seem to think.
"James Hansen". Pretty much anything he's ever said in public. No, it's not hard at all. It's hard to find a scientist's name in the (conventional) media who is not playing politics. (In this case I don't include the explicitly-science section of the papers. There you get your choice of either a journalist playing politics with science or a journalist not understanding what they are writing about, or both, but that's not the scientist's fault.) You think it's hard because we've become so used to it you can't see it anymore but scientists do hardly anything but make ought statements instead of is statements anymore.
It doesn't count that it's really important!!, like the global warming scientists. It's still scientists in politics, not merely saying what is happening but what we should do about it and when. It doesn't count that you like what the political scientists are saying, it's still scientists in politics.