What action would Mr Trump take if he decided not to accept the Presidential Election result?

His only recourse would be through legal channels. He could demand a recount in every single voting polling station in the US and would most likely demand that the taxpayer pay for the recount. If the Republican Party refused to defray the costs of a recount then Trump would most likely take the GOP to court. That being said it would cost Trump megabucks of his own money to launch court proceedings.

However in the US voting system it is the Electoral College who votes in electing the president, not the people.. Each state has its own rules in choosing its Electoral College representatives. Some states go by the popular vote, some states do proportional representation based on the popular vote, some states ignore the popular vote altogether.

There have been cases in the past when American presidential electoral results have been seen as unreliable by both domestic and foreign observers. The most famous involved John F Kennedy. The Democratic Political Machine was widely believed to have used underhand means to get him elected.

Well, there are legal means to contest election results. He can go to court. Problem there is if he loses by a landslide it's going to be hard to prove there was so much "fraud" going on that he lost multiple states due to criminal shenanigans.

He can contest the results state by state in state courts. OK, who is going to pay for that? I'm pretty sure the RNC is NOT going to pay his legal fees, so he would have to fund multiple state challenges out of his own pocket. I'm pretty sure he would ultimately lose and as the losses piled up in state courts he would tire of the "game" he is playing and probably concede in some assholeish way.

Of course if the rubes he has duped (aka "the suckers"), i.e. his supporters, decide to go paramilitary then I imagine they will end up like the Bundys did in federal jail.

He could try challenging the results at the state level. This would basically be demanding a recount.

But this could only be done in the case of a close result. Losing by a landslide isn't normally grounds for a recount.

File a law suit on some bogus accusation of a "fix" having taken place, he has the $ to tie the result up in the supreme court for an age. He is incapable of accepting defeat, his ego and his rampant megalomania would not allow it.

He is Americas own Orange Apocolypse

The plump chump Donald duck-lips tRUMP will probably phart in front of Hillary and walk away... what else can you expect from a lowlife like him?

He'll file lawsuits challenging the legitimacy of the results if the election is at all close. That's what he meant.

start up his own Trump network with 24/7 news on Hillary and the corruption of the DNC

He could cry all he wanted but I doubt he would have many backers.

He would stamp his little feet and yell "it's not fair".