On Tuesday, August 9, there's a primary for the seat held by Paul Ryan, the House Speaker. It's in the news -- Ryan is being challenged in the Republican primary by a hitherto little-known businessman, Paul Nehlen. There's also a contested primary on the Democratic side. On Tuesday, Donald Trump pointedly refused to endorse Ryan, which doesn't necessarily reflect any Ryan weakness in the district (more like Trump and Ryan's irreconcilable differences.) But Ryan was vulnerable before, and he's more vulnerable now.

That's where Wisconsin Democrats come in: Wisconsin's open primary tradition means you can vote in Ryan's primary -- which gives you, through a harmonic convergence of circumstance, a strange and shocking power. With one vote you can boot the most powerful national Republican in the country, an ideological zealot who will never be dissuaded from enacting policies inimical to Democratic ideas and interests. With one vote, you can kill the pending Trans Pacific Partnership (TPP) trade deal. You can kill the GOP's longstanding plan to voucherize Medicare. Kill Ryan's scheme to pack all welfare programs into one capped stream of money and let states spend it as they wish. Kill his plans to promote guest workers and in effectively encourage more immigrants to come here and bid down wages.

Why would you not do that?

In 2014, remember, thousands of Democrats in Virginia crossed over to vote in the Republican primary against ambitious GOP rising star, Majority Leader Eric Cantor. That may have made the difference in the shocking defeat of the now ex-rising star by a little-known professor, Dave Brat.

Why not do it again?

Is the problem that Paul Ryan's a statesmanlike figure who represents the best Republicanism has to offer? Hardly. The key thing about Ryan is that he's a true believer in the unhindered market. He's certainly a true believer in free trade -- something that only 11% of his own party thinks helps boost wages, never mind Democrats (who disdain free trade by similar lopsided margins). Ryan recently told a Koch brothers gathering he'd lead the fight for expanded trade deals despite the opposition within his own party (a "progressive" tendency he vowed to "repudiate"). If Ryan returns to the House -- where he'll almost certainly remain Speaker -- he will probably try to pass the big TPP trade bill this year, and he will probably succeed.

What have free trade deals done for Wisconsin industry?

Ryan's also a principled believer in the 'free movement of people'! In other words, open borders. He can't quite come out and say it, but it's close. He's explicitly called for guest worker programs to import low-wage laborers so farmers don't have to "raise wages too much" (from about $12 an hour) for Americans who milk cows. More generally, Ryan calls for a system where "labor supply and demand can meet each other" -- translation: employers can bring in as many low-wage workers as they want. Ryan's "probably the most ideologically committed open borders person in Congress," according to Mark Krikorian of the Center for Immigration Studies.

And you know those 150 Abbott Laboratories workers near Waukegan who had to train their foreign replacements before being laid off? It all happened under the "H-1B visa program," which is supposed to bring in only foreigners who have "specialized" skills Americans lack. You can expect Ryan to do everything in his power to expand the flow of such American-replacing guest workers. And to favor the legalization of undocumented immigrants over actually securing the border against future flows of illegal workers -- which, after all, is just another word for free movement of people!

In Washington, Ryan is considered a "philosopher" because he talks about abstract theories and principles -- especially the Economics 101 theory that unlimited trade and immigration maximize overall well being. Of course, as the theorists reluctantly acknowledge if pressed, there are "winners and losers" in the process. The Winners are mainly investors (eg. the rich, and Wall Street). The Losers ... well, that's you: American workers who now have to compete with all the impoverished people on the planet. But don't worry! You see the bonanza from free trade and immigration is so great, the Winners can afford to compensate the Losers who can't find jobs. So nice of them! Of course that is only in theory,

But what Ryan really lives for, apparently, is cutting "entitlements," which means Social Security and Medicare. He's pushed to "privatize" the former and turn the latter into a voucher-style program in which people have to constantly choose (and rechoose) between competing private insurers.

Would you rather have Medicare, where you sign up and they pay the bills, or a complex scheme, very much like the troubled Obamacare "exchanges," in which you're always scrambling to avoid being gouged, always worrying that the plan you signed up for won't cover the drugs or operation you need or even be there next year?

If you don't like Medicare, by all means vote for Ryan. But if you do, you can end the Ryan threat for good -- just by exercising your Wisconsin privilege to vote in the primary you choose to vote in, and voting for Ryan's opponent, Paul Nehlen.

It'd be worth bouncing Ryan even if his opponent was a putz. So it's a bonus -- gravy -- that Nehlen, is instead an appealing fellow, a local entrepreneur who has successfully worked with union and non-union shops, and who fundamentally agrees with prevailing Democratic skepticism about big trade deals -- NAFTA and TPP etc. He favors bilateral deals in which we can instantly slap tariffs on countries that manipulate their currencies or violate labor standards. His test is whether a given deal helps average Americans -- not whether it helps Wall Street more than ithurts the 'Rust Belt'.

But if you don't like Nehlen -- if you want to instead elect one of the Democrats who are running -- fine. You can still vote for Democratic nominee in November after bouncing Ryan now. It's win-win.

OK, there is one downside. Wisconsin Democrats who vote against Ryan in Tuesday's GOP primary for Congress can't then also vote in Tuesday's Democratic primary for local offices -- county clerks and treasurers, maybe an assembly race. Especially you are a party regular, those races can be very important -- and if they're that important to you, by all means vote in the Democratic primary.

But if you're not a party regular -- if you're just a voter worried about the direction of the country -- deciding which primary to vote in should be an easy choice. Which is the bigger threat: that a zealot like Ryan will push trade and immigration deals and destroy the possibility of decent paying jobs, while making the Social Security safety net as insecure as the economy -- or that a turkey will get nominated to be Register of Deeds in Rock County?

It's up to you.

Mickey Kaus is author of The End of Equality and blogger at www.kausfiles.com.