Thanks.
Sounds like 1824 stays pretty much as OTL, and probably not a lot changes until possibly 1836, which might get thrown into the HoR, as could (less probably) 1856.
I speculated on the effects in soc.history.what-if back in 2006:
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I don't think that the amendment would have made much of a change in
presidential elections in the 1820s through the 1840s. (It is just
possible that it would have led to the 1836 presidential election going
into the House, but I doubt it; Harrison would certainly pick up some
electoral votes in New York and Pennsylvania and Connecticut, and Hugh
White might do so in some southern states; but this would be balanced by
Van Buren picking up electoral votes from Harrison in Ohio and New Jersey,
and from White in Georgia and perhaps Tennessee.
http://psephos.adam-carr.net/countries/u/usa/pres/1836.txt In any event,
Van Buren would still win in the House if the election went there. I'm
not sure what the effect would be in 1848: perhaps Van Buren would have
carried more congressional districts than in OTL--indeed, I'm not sure he
carried any--if it were thought that he had a chance to send the election
into the House. But the odds are pretty strong against his actually being
able to do so.) But it would obviously greatly affect the rise of the
Republican Party in the 1850s. Such a party--with practically no support
in the South, and substantial opposition in much of the North--would have
much less chance than in OTL of an Electoral College majority for many
years (though it would have a better chance with the district system than
it would with a strictly proportional division of each state's electoral
votes). In 1860, Lincoln might carry *one* district in a southern state
(Frank Blair's St. Louis, Missouri district); but this would be far
outbalanced by all the districts he would lose in states he carried like
Illinois, Indiana, New York, Ohio, and Pennsylvania. (See
http://en.wikipedia.org/wiki/Thirty-seventh_United_States_Congress for all
the Democrats elected to the House from these states in 1860. To be sure,
some districts that narrowly voted for a Democratic Representative may
have narrowly voted for Lincoln, but the list is at least suggestive.)
Furthermore, attempts to form anti-Lincoln fusion tickets might succeed in
some congresional districts in states where such attempts failed on a
statewide level in OTL. The race would probably go into the House, where
each state delegation would have one vote, and where Lincoln's chances of
victory would be slim.
(One thing I am wondering about: would the district system have sent the
1856 presidential election into the House?
http://psephos.adam-carr.net/countries/u/usa/pres/1856.txt Fillmore
certainly would have done better, since he presumably carried several
congressional districts in southern states like Kentucky, Louisiana,
Tennessee, and Missouri, where Buchanan won fairly narrow victories; and
perhaps in North Carolina and Georgia as well. And Fremont would have
gotten some electoral votes in Buchanan states like Illinois, Indiana, and
perhaps Pennsylvania. Furthermore, it is possible that attempts at a
Fremont-Fillmore fusion in the North, which in OTL failed on a statewide
level, might have been implemented in some individual congressional
districts in, say, Pennsylvania or New Jersey. OTOH, Buchanan would have
picked up votes in relatively close Fremont states like Ohio and possibly
Connecticut and New Hampshire (and even in the one state Fillmore carried,
Maryland) and probably in New York, so maybe he would still have gotten a
majority in the Electoral College...)
https://groups.google.com/d/msg/soc.history.what-if/VG0dvMkIOsI/fduIHi1JwXsJ
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Rich Rostrom, later in that thread, disagreed with me about it not having much short-run effect, arguing that it would for example give states an additional incentive to gerrymander and might lead to Congress cracking down on gerrymandering.; that it might lead to a consolidation of congressional and presidential election days earlier than in OTL; that the parties might be less inclined to nominate candidates from states rich in electoral votes; etc. See
https://groups.google.com/d/msg/soc.history.what-if/VG0dvMkIOsI/9GPFXFz5YhcJ for my reply:
"It may be that I underestimated butterfly effects of adopting the district
system, but I am still not convinced that the basic workings of the
Jacksonian party system would have been changed that much. (Also, remember
that this would not be a pure district system: two electors would still
be chosen at large from each state, so carrying *states*--not just
congressional districts--would still be important in political strategy.)"