As tiresome as the endless US presidential primary process can be, there's a value in the endurance test involved.
The candidates' strategies, flaws, stamina, ability to adapt, political nimbleness and resilience are tested. The effectiveness of policies and messages gets tested. The strategic thrust of the overall party is tested.
Last week's Democratic debate, when compared with the earlier editions, showed how candidates and the race have changed and yet stayed the same.
Just over four months until the first contests, there's a breakaway trio at the top, a couple of nearby contenders and then the main pack.
The RealClearPolitics.com average of national polls shows former Vice-President Joe Biden leading with 26.8 per cent over progressive senators Bernie Sanders with 17.3 per cent and Elizabeth Warren on 16.8 per cent. Needing fresh momentum are Senator Kamala Harris on 6.5 per cent and Mayor Pete Buttigieg with 4.8 per cent.
Biden's approach to wrap himself in former President Barack Obama's ongoing popularity with his party has been transparently simple, and its strength has been its simplicity.
The most recent Quinnipiac University poll showed Biden drawing 41 per cent of party moderates, 30 per cent of whites and 46 per cent of blacks. Historically, a Democratic moderate has a better chance of winning the nomination than a progressive, and it's hard to triumph without African American support.
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Over several debates Biden has gone from a listless beginning to last Friday where he showed aggression and steadiness. Biden's main task is to reassure Democrats that he's got this, but his gaffes unnerve many and make him vulnerable to questions of whether he's still up to it.
The leading trio did well enough in the latest debate to maintain their positions. Warren has improved in the polls, relentlessly pushed her plans and lately has drawn large crowds. But doubts remain over whether Sanders and Warren can expand beyond their white liberal support base and are simply restricting each other.
Harris, who has had a rollercoaster campaign, has made the most adjustments. She still struggles to clearly define who and what she represents.
There was belated awareness in Friday's debate that Trump should be a greater focus of discussion and that attack lines need to be laid now. Former congressman Beto O'Rourke is finally finding his voice as a candidate in takedowns of Trump over gun violence and advocating a buyback scheme for assault weapons.
Biden remains a controversial frontrunner. Party activists and part of the US political media are less than excited to see him there given his status as a Washington fixture for decades.
There are candidates who would represent generational change if voters preferred it.
But Democrats chiefly want the person most likely to beat Trump. National polls show that person is still Biden, who leads the President in RCP averages by 11.5 per cent.