With Donald Trump continuing to outpace all rivals at the primary polls, some Republican leaders are considering a desperate, rear-guard effort to keep the polarizing candidate from winning the party’s nomination: a brokered convention....

...if Trump feels spurned by the party, he could mount a scorched-earth third-party write-in campaign to sap support from the ersatz nominee. Meanwhile his supporters, having had their millions of votes effectively nullified by a few thousand insiders, could be lost to the Republicans for years to come.