Additionally, the Twentieth Amendment is subsequent to the original constitution and to Amendment 12 and, any discrepancies among them are resolved by resort to the most recent enactment (Amendment 20) since those who enacted it were presumed to know the constitutional provisions they were amending.
A newly elected Congress takes office on January 3 after election at noon by Amendment 20, Section 1.
Now, imagine that the vicious (on all sides) GOP uncivil war continues and, as one example, Trump is close to 1237 delegates but not quite, say 1190. The RNC makes changes in convention rules before the convention goes into session which rules may be changed by convention delegates but ONLY after the matter of Credentials has been resolved.
The Credentials Committee reports to the convention its rendition (generally uncontroversial to this point) of who the delegates and alternates are and moves adoption of the Credentials Report. A delegate on that list from, say from North Dakota moves to unseat four large Trump delegations in one motion, say New York, Illinois, Florida and California. At that point, the delegates and alternates listed in the Credentials Report from those four states cannot vote on their own credentials (in ordinary circumstances they are viewed as having a conflict of interest).
Nonetheless, a Trump delegate from any unchallenged state delegation moves "to divide the question" essentially to vote on the challenged delegations one by one so that the others can vote unless previously eliminated. Paul Ryan-o, chairing the convention, takes a voice vote, refuses to hear objections or points of order and quickly slams down the gavel ruling that the question will NOT be divided. The remaining delegates vote to unseat the four delegations. Trump now cannot win on the first ballot and probably but not certainly no one else can be nominated on that ballot either.
On a second and any subsequent ballot, many remaining delegates are no longer bound by law (not that such laws are enforceable for any but the delegation from Ohio. Delegates often change even on the first ballot and no one is EVER prosecuted criminally.
If a Connecticut delegate defects on the first ballot from Trump to whomever, that defection takes place in Ohio at the convention and Connecticut has no criminal jurisdiction over violations occurring in Ohio and Ohio has probably no jurisdiction to apply Connecticut criminal law (if any). Defectors from wherever are home free since the same situation would prevail for any state's delegates or alternates OTHER than Ohio.
Trump is likely but not definitely defeated. The better organized GOP-E rams through a ticket of ITS choosing, claiming that someone MUST put a stop to this embarrassing anarchy. El Jebbe? Moral Monster Mitt Romney Redux? John McCain? Melvin Schlabotnick? No matter. The victory is to the better organized who have an actual plan which we are not privileged to see in advance.
Ahhhh, but this is high risk pinball. A number of experienced and eloquent seated delegates from various states force themselves into control of floor microphones to raise hell over the high-handed GOP-E tactics. Say that Ryan-o lacks the cojones to cut off their microphones, which he can arrange (for Trump that wold be a best case scenario. IF and ONLY IF they can stampede delegates who did not get chosen to support Trump but were either uncommitted or, preferably, committed to Cruz and/or Kasich and/or Rubio and in sufficient numbers to overcome the slightly inexperienced Ryan-o and cause him to panic, Trump might be nominated by outraged supporters of others defecting to Trump.
In that event, GOP-E, if sufficiently determined to stop Trump at all costs, puts El Jebbie (in all likelihood) on the ballots of as many states as possible to so divide the Republican inclined voters as to defeat Trump even if that means Comrade Grandma as POTUS.
OR the GOP-E prevails on the nomination by these tactics (not caring about the general election outcome) and Trump goes third party with the same result of Comrade Grandma as POTUS.
Meanwhile the mutual hatred and bitterness in GOP ranks over this three-ring circus and all those very uncharitable remarks by every Republican candidate's most extreme partisans then cause the loss of the Senate and maybe even the loss of the House. I can see Ryan-o paying the price of being defeated by primary or general election in Janesville, just north of where I live in Illinois. No matter, he will be raking in $3 million a year guaranteed for life for his treasonous behavior.
Think Virginia 7 was mad at Eric Cantor? You ain't seen nothing yet but the GOP-E will also take the trouble to take out some of our best non-GOP-E Republican Congress Members because the GOP-E despises above all else non-GOP-E members of the GOP. The GOP-E will make deals with Comrade Grandma to REALLY throw monkey wrenches in our works in exchange for the usual lobbyist favors they passionately crave.
AND, in case anyone entertains the delusion that Comrade Grandma won't be caught dead serving the business interests, check out those who provide oceans of cash to the Clinton Family Crime Foundation, check her Senate voting record, check even Obozo's abandonment of everyone BUT communists, Islamofascists AND the rich and powerful and corrupt.
I could be wrong about some of this and I welcome correction from anyone more knowledgeable in law or parliamentary procedure.
There's more but that should suffice for now. I am pinging a few others to share the above.
Currently, under Section 3 Congress just adverts to the current line of succession law. They should pass a separate one for this situation but they haven’t. So if the House and Senate are deadlocked or everyone is dead, currently the Speaker becomes president on January 20. BUT (and this is very important) the 20th Amendment makes clear that if the problem is just that the House and Senate are deadlocked, they continue trying to elect someone and when they do that person steps up. So even after January 20 the House would keep voting —one state one vote—until they pick someone. March 4 changes nothing.