Readers Write (Sept. 16): Blood-donor rules, chronic drunken driver, presidential race, refugees and immigration, beliefs in context, the future of football

My blood type is O-negative, and I am a sexually active gay man. Whose head just exploded? I ask because I have a universal blood type; it can be given to anyone. If there is an emergency and the doctors don't know your blood type, they'll give you O-negative. Unfortunately, only 7 percent of the U.S. population has this blood type, so it's always in short supply. I have wanted to give blood for years, but I have been banned. The fact that I have been in a monogamous relationship for more than 20 years and have tested negative for HIV doesn't matter. However, if you are a heterosexual man with multiple partners, you can give blood. Those are the rules. Thoughts?

Regarding "He has 12 DWIs, and counting" (Sept. 15): I think those of us who have survived Douglas J. McCready's driving are entitled either to an explanation of why he was allowed to have a valid driver's license after his 12th drunken-driving conviction, or the name of the decisionmaker who made this possible.

Three months ago, the pundits predicted that Donald Trump would disappear in a few weeks. Now the prediction is a few more months. The real question that we should be asking ourselves is who will he have as his vice president? If Trump is our next elected president, 18 months later he will be impeached. Why? Because all of his big lies will be revealed in combination with his total reversal of "principle," as he funnels huge profits into the pockets of the 1 percent. "A wolf in sheep's clothing." "A leopard cannot change its spots." These come to mind, as well as the word "sucker," when I think about this future.

The editorial cartoon by Tom Toles on the Sept. 15 Opinion Exchange page held a mirror up to Trump's "stupid, stupid, stupid" exhortation, perfectly capturing Trump's mesmerizing danger. I don't know how to explain the infatuation with Trump. When one-third of voting Republicans say Trump is saying what they are thinking, ignorance comes to mind. The rise of this blowhard-cum-nonpolitician candidate is a dangerous threat to our society.

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Oh, come on! People are thinking a Trump victory is possible? Yes, he is leading the polls. Doesn't anyone realize that sane people split their choices among 16 candidates, and will almost certainly coalesce behind one of the others as their first choice drops out. The real test will be as more candidates drop out.

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In an obvious effort to grab attention from Trump, Walker is digging up his old technique: Divide and conquer workers by stirring jealousy in those without union benefits against those with — all to the benefit of profit-hoarding employers everywhere. To understand what's going on, all we have to do is remember the first letters of Scott's last name: Wisconsin's Anti-Labor, Koch-Emissary Republican.

The Syrian refugee crisis is an opportunity for the U.S. Our country cannot afford to fight the migrants' war for them, but we should welcome those who are fleeing the chaos and tyranny of extremist Muslims. These are professionals and people from all walks of life who would be contributing members of the community. Rather than spending our money on iffy programs to influence young Muslims against the extremist direction that we most fear, we would be better served by bringing hundreds of thousands of the refugees to our welcoming, free country.

What better deterrent to positive views of Muslim extremism than an influx of people who have seen what the extremists stand for and will personally attest to why no one would want to support them, much less join them? These refugees will naturally find their way to all parts of the American Muslim community, and will be far more effective at spreading the message we want Muslim youths to hear.

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Although I find the safe haven given thousands of Syrian, Iraqi and Afghan refugees into the European Union and other countries laudable, I can't help but feel sad and angry that equal effort wasn't made to rescue the people of Darfur as the atrocities in Sudan came to light.

No need to be subtle — could it be the color of their skin?

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What is the true cost of immigrants, and why is it never discussed? What does it cost to teach English as a second language to whole families or individuals? To provide housing and transportation for an undetermined length of time? To teach adults a skill that will fit into our society. Job placement? Educating youths in the public education system? Medical care for families and individuals?

Specious at best is the logic of the quote by Arthur Schnitzler (L.K. Hanson's "You Don't Say" cartoon, Sept. 14): "Martyrdom has always been a proof of the intensity, never of the correctness, of a belief."

Beliefs, by their very nature, are neither "correct" nor "incorrect." At most, beliefs are "correct" only within the culture or tribe that espouses those beliefs.

Regarding Patrick Reusse's Sept. 10 column ("Football's expiration date not as far off as you think"): I don't disagree with his facts on the decline in football participation, based on locale. I have a son who played one year of football for a St. Paul Catholic school, as a starting safety and receiver, then decided to quit because "I don't mind hitting, but I don't want to get hit that hard."

But I think there's an element missing in the idea that football will "expire." I'd call it the "UFC, NBA, Rollerball" hypothesis. Of course, "Rollerball" is a super-violent, ultra-popular fictional sport involving a steel ball and motorcycles on a roller-derby track. But look at boxing, the ultimate concussion and contusion sport. Hasn't it been eclipsed by the mixed martial arts ("ultimate fighting" — yet more violent)? And the NBA. When I played basketball, the focus was on the ball and body contact was minimal. The NBA and the NFL often aren't that far apart these days.

I think that with astronomical money involved, and the quest for ever more sensational entertainment, the NFL will continue. It probably will grow, domestically and globally. There's always someone out there willing to make and take the huge hits for millions of dollars. Maybe they're not in Eden Prairie or Colorado; maybe they're in New Zealand, but they're out there.