At the end of May, Florida Sen. Marco Rubio led the GOP field. He was followed closely by Jeb Bush, Mike Huckabee, Scott Walker, Ted Cruz and Rand Paul.

Walker and Rubio were close to tied, given the margin of error. Donald Trump was in the back of the pack, polling behind former New York Gov. George Pataki.

What a difference a summer makes.

Today, as the nation approaches Labor Day, Donald Trump dominates the field. His closest competitor, with less than half the support of Trump, is retired neurosurgeon Ben Carson.

Rubio, Cruz and Walker are tied in 4th place at 7 percent. Rand Paul, whom the media thought would recast the Republican party, has faded to tenth, just edging out Chris Christie.

Rubio, Walker and Paul each led the field in various polls throughout the early days of the campaign.

It is important to note, these are national polls and don’t necessarily reflect the situation on the ground in the early voting states. “Don’t necessarily” being the operative phrase in that sentence. State and national polling won’t stay independent of each other for long, absent specific quirks within a state.

Walker, for example, is still in a strong third place position in Iowa. Throughout June and July, however, Walker had a solid lead in the first voting state. Many pundits considered Iowa to be Walker’s race to lose. Developments in national polling suggest Walker is on his way to doing just that.

Regardless, as the campaign enters a new phase of the race, it is worth revisiting what has happened to three leading figures, each of which could stake a claim on being the future of the party. It is yet another parable for why we actually go through campaigns. The best laid plans, and most convincing musings from pundits, do occasionally run into the brick wall of reality.

The steady drop in the political fortunes of Rubio and Paul are understandable, in hindsight. Both are essentially one-trick ponies who are each entering their fifth year on the national stage. Rubio is young and telegenic, has Cuban parents and delivers a very good speech on the promise of America. He is exactly that peer in high school your grandparents would point to and say what a nice young man he was.

Rubio’s Achilles heel is that he listened to some very bad political advice, mistook his own life story as some kind of archetype and became the public face of a very flawed immigration bill authored by Democrats Chuck Schumer and Dick Durbin.

At the beginning of the Presidential campaign, he had half-persuaded some gullible people that he accepted his missteps during that debate when news reports over the summer exploded with violent crimes committed by illegal immigrants who had been repeatedly released from detention. Because he believes that biography is policy, he has been flat-footed to respond to growing voter anger about the government’s abject failure dealing with the current immigration crisis.

Unsolicited advice for Rubio: We all get that most immigrants are good people simply seeking a better life and that, on balance, immigration has been great for America. Please stop with those lectures and address the feds ignoring established law, the recent crime waves and the terrible drag on wages and wage growth sparked by our current open borders policy.

Rand Paul represented a strong libertarian strain in the recent Tea Party movement. His mini-filibuster on NSA spying and the fed’s expanding use of drones was an important event and harkened back to a time when the Senate actually discussed big, important issues. He exposed the statist impulses of Republicans like John McCain and Lindsey Graham.

He went further and took an optimistic, hopeful conservative message into minority communities, making a strong case for free markets and the rights on individuals. It was something the Republican Party hadn’t done since, well, ever. He raised important questions about law enforcement, the drug war and prison reform. It was a welcome tonic to the tough-on-crime shibboleth of most politicians.

But, then the medieval death-cult ISIS exploded on the scene and Rand Paul’s foreign policy thoughts, which are tinged with his father’s blame-America-first frame, looked out of place. The left began an all-out assault on police and law enforcement, which dulled conservatives’ appetite for some still-needed reforms. Worse, though, Paul seemed to be consumed with his image as a Republican “iconoclast.” The media painted him as a Republican “outsider” so he believed he was, even as the voters’ assessment of that label was changing rapidly.

Paul still talked like a Senator and took aggressive steps to ensure he could run both for President and for reelection to the Senate in Kentucky. Paul thought his views made him an outsider to the party establishment, but his heterodox views were no longer what voters considered outside the establishment.

Walker’s fade is a bit harder to understand. A sitting Governor of a swing state, he had accomplished a host of very conservative reforms in a state that was not necessarily inured to them. He stood up to a very powerful public sector and overcame opposition from within his own Republican party to push the envelope on reform. He won three statewide elections in four years. Walker also has a compelling personal story that is the opposite of the resume of the political class.

Yet, on the trail he underwhelms. His performance in the first GOP debate was forgettable. He relied on canned talking points at the exact moment voters were most interested in authenticity. Another governor, John Kasich, improbably out-shined him. Kasich has many unconservative positions, but he comes across as a real human being, instead of a political candidate. Walker looked as if he had been debate-prepped into wallpaper.

As the pundits repeatedly tell us, we are still five months away from the first votes being cast. We are, however, entering the very serious phase of the campaign. Big campaigns, like Rubio, Walker and Paul, are burning through $1 million a month, just to keep the lights on. In just a few months, major decisions on advertising will have to be made.

The national beauty contest, which the three have lost at this point, will give way to a state-by-state slugfest. Walker is still betting on a strong showing in Iowa to reignite his campaign. Paul is hoping that caucuses, especially in the Western states, can give his campaign a delegate boost. Rubio seems to be placing a firewall in South Carolina and his home state of Florida. At some point he will have to decide whether he wants to be the establishment alternative to Bush or the second-choice of other more conservative candidates. He’s tried to be both, but that strategy isn’t working.

Of course, there is still a real possibility that the voters’ anger with Washington and national Republicans grows rather than abates. In September, Republicans will return to Congress and will likely avoid all confrontation with Obama to pass a spending plan for the government. They are completely out of step with the mood of the country and it is unlikely they would change course even if they were aware of it.

When that happens, the current logic-defying stampede to Trump or Carson or Cruz will only increase. The dissection of the Rubio, Paul and Walker campaigns will no longer be a topic of current politics, but a subject for history.