Donald Trump has a commanding lead in the race for the Republican presidential nomination and is the only candidate with a realistic shot of clinching the prize without a convention fight.

Still, his path to the magic number of 1,237 delegates is a narrow one that requires victories in winner-take-all states like Delaware and New Jersey, and strong showings in delegate-rich states like California, New York, Indiana and Pennsylvania.

For Mr Trump to secure the nomination he'll have to win 53% of the remaining delegates. That number rises to 56% if he is convincingly beaten in Wisconsin on Tuesday.

He could fall slightly short of that number and still cross the finish line before the Republican convention's opening gavel if he can pick up the support of enough of the hundred-plus unpledged delegates, which include those from candidates who already dropped out or from states that don't holding nominating contests, as well as party officials.

If Mr Trump continues to see his head-to-head match-up numbers against potential Democratic candidates tank while he is buffeted by controversies and conflagrations, however, such a consolidation of support grows less likely.

David Fuller's view

“Democracy is the worst form of Government, except for all the others.”

Attributed to Winston Churchill

Here is another of several Churchill quotes on democracy:

“How is that word ‘democracy’ to be interpreted? My idea of it is that the plain, humble, common man, just the ordinary man who keeps a wife and family, who goes off to fight for his country when it is in trouble, goes to the poll at the appropriate time, and puts his cross on the ballot paper showing the candidate he wishes to be elected to Parliament—that he is the foundation of democracy. And it is also essential to this foundation that this man or woman should do this without fear, and without any form of intimidation or victimization. He marks his ballot paper in strict secrecy, and then elected representatives and together decide what government, or even in times of stress, what form of government they wish to have in their country. If that is democracy, I salute it. I espouse it. I would work for it.” —House of Commons, 8 December 1944