26350 And I believe that the devil is ready to repent! But..

I kept feeling there was some sort of message in this thing, what with two unlikely Presidents of the US of A (one past and strangely rather fondly remembered), and one yet to be. The across clues, with a bit of judicious and creative punctuation, almost read as coherent sentences, with the two long ones in the middle referencing our yet-to-be-president’s policy on aliens, Mexicans, Muslims – hell, anyone he just doesn’t care for. I dallied for 20 minutes on this, taking time to be sure of a couple that I couldn’t initially justify, but there’s not much to test the gaps in GK, except perhaps for the “flower” in 6 and the sticky (?) fluid at 26,
Here’s how I turned Wasser into Wein.

Across

1 DISCIPLE Mark, for example
Not officially one of the Big Twelve, and not the sort of name you’d give to a good Jewish boy. Thought by some to be the “boy going around in the buff” when escaping from Gethsemane, exclusively seen in the gospel that bears his name. PLace “visits” IE (that is) attached to a DISC. Our grandchildren may well have to ask why “record” means disc.
5 EVADES  Shakes off
See what I mean? Disciple (sc Mark) evades…  Journalist translates by convention to ED(itor), and is inserted into SAVE, bar as in all bar one, before the assembly is reversed
9 TRUMP CARD  Winning move
Initially T(railing), behind = RUMP, and character CARD (Chambers “a comical or eccentric person” now rather dated). As a whole, the clue looks like a commentary on the current race for the White House: could this be co-incidence? I think we should either be told or turn it into a conspiracy theory.
11 SAFER  Less adventurous
Today’s hidden in travellerS A FERry. Trump card safer? Really?
12 CHERISH  treasure
C(aught) + HER (woman’s) + H(usband) with an inserted 1’S.
13 EQUERRY  Queen’s escort
Key (pick any one of 7) is E, doubt is QUERY, and add in an R(ex) for King. Cherish equerry – there’s a royal scandal in there somewhere, possibly involving Diana.
14 EXTERMINATION  genocide
A name no longer used would be an EX TERM. One country would be 1 NATION. Staple together.
16 COLD-HEARTEDLY  In an unfriendly way.
You need to get the letters of CHAT, ODDLY and LEER squiffy, to get the result you’re looking for. Extermination cold-heartedly? There’s a royal scandal in there somewhere, possibly involving Diana. Or maybe (see above) the great Donald’s foreign (and selective domestic) policy.
20 LOGBOOK  official record
Part of the United Kingdom is GB, as it’s not the UK until you include Northern Ireland. Appear is LOOK: try “that appears/looks familiar” You also need the O from Old before assembling the parts as instructed.
21 ECLIPSE  Obscure
Extracts of paper are CLIPS (though more commonly clippings, clips being bits of film), and the middle of speech is EE. Assemble insertionally. Logbook: eclipse? I found one! I also found possible product placement, as Eclipse Logbook appears to be a lorry driver’s essential record keeping programme. Anybody care to verify?
23 ISSUE Result
Such a lot of lies would be a tissue. Ignore the first letter like it says.
24 TWO-TIMING  Adulterous
Couple TWO, man TIM (might just as well be) and ING(e) our horizontally challenged Swedish girl.
25 NUDIST &lit
And rather a cute one. On the grounds that “boy” signifies a diminutive form of a name (in exactly the same way as “man” in the previous clue shouldn’t), it’s SID, reversed in a NUT, a buff as in, say, film buff.
26 GLUHWEIN  This German’s possibly drunk
Where, in keeping with German grammar, drunk is the verb. Play with the letters of WHILE and GUN. Gluhwein is “hot, sweetened, spiced red wine, mulled wine as prepared in Germany, Austria, etc”. “Issue two-timing nudist Gluhwein” in celebration of Freikörperkultur?

Down

1 DETACH free
D(iamonds) + ETCH (cut) and the capital of A(ngola). Luanda doesn’t fit.
2 SAUCE  Impudence
Sounds like “source” for non-rhotics. Source may well not be the kind of author you were thinking of before light dawned.
3 IN PRINT  on the streets
I’m guessing there may be the odd careless imprint here. the even letters (overlook the odds) of signs are IN. Type gives you the PRINT.
4 LEATHERJACKET  a swimmer
I think it has to be the fish rather than the cranefly larva as the latter doesn’t swim. A biker might wear a leather jacket with a gap in the middle.
6 VISTULA  flower (sc river)
Though the Poles call it Wisła. Flows through most Polish towns you’ve heard of, some of which you can even pronounce. For our purpose, a view is a VISTA and the extremes of U(nusua)L provide the missing letters.
7 DEFORMITY Imperfection
A kind gives FORM, and God is DEITY, which choirmasters insist is pronounced dee-ity
8 STRAYING  aberration
OK, I think this is swindle: STING and note: RAY (“a drop of golden sun”, today’s free gift of an earworm. You’re very welcome.) Chambers confirms, not sure I would.
10 DYED IN THE WOOL  Incurable
And a “treatment” of OLDIE THEY’D NOW
14 EULOGISED  that’s raved about
“Trip” the letters of LOSE GUIDE.
15 SCALLION  Vegetable
CALL is provided by demand, one again gives 1, and your lad, your SON is required to eat the two. It’s an onion of several kinds. Or a leek.
17 HOOKERS  Rugby players
Gentlemen, there are ladies present. Another “alternate letters” feature, this time hEaRd, this time breaking into HOOKS, catchy phrases in refrains and such.
18 DOLTISH  Stupid
Officer is LT (lieutenant, prononce it how you will, though I can’t see the F) Idiot primarily I, both placed into DOSH, British (?) slang for money.
19 REAGAN  president
Almost back is REA(r), win is GAIN, from which you lose the I (current, physics). Here’s the song referenced in the headline.
22 PRIZE  Reward
Two forms of energy are E and ZIP: reverse them and insert R(ight)