The 11th version of the Republican Party presidential debate circus provided one more frontal assault tonight by the three remaining viable challengers to frontrunner Donald J. Trump.

I’m going to join others around the country in asking: What took these guys so long to muster up the guts to go after this guy?

Mitt Romney this morning unleashed a blistering critique of Trump. He challenged his temperament, judgment, his business acumen, his ethics, his morals, his shallowness … have I left anything out?

Then tonight Ted Cruz, Marco Rubio and John Kasich continued their assault on Trump.

This comes after months of seeking to “stay on the high road.” They were cowed by Trump’s lambasting of others who dared criticize him. Trump pointed gleefully at how others who would take shots at him would see their own campaigns evaporate.

Rick Perry, Bobby Jindal, Lindsey Graham? All gone.

Jeb Bush? Toast.

The rest of them? See you later.

Cruz wants to be the last man standing in the anti-Trump brigade, according to the Texas Tribune. But another strategy is beginning to develop: It is to keep the field crowded and denying Trump the ability to gather enough delegates to win the GOP nomination outright on the first ballot at the party convention this summer in Cleveland.

Trump’s incredible crassness has been ripe for criticism all along.

His foes, such as they’ve been to date, have chickened out.

I’ll give former Texas Gov. Perry credit, though, for sticking it to Trump early — only to see his own presidential campaign fizzle out.

Were the other guys afraid that would happen to them as well?