The decision by Wisconsin Governor Scott Walker to leave the Republican presidential race is a prime example of how the debates can't win you the nomination but they can lose it for you.

It was only a few months ago that the deeply conservative Walker was leading the polls. This clean-cut, Harley-riding, family man attracted big money supporters. Among them the Koch Brothers, seen as power brokers in the Republican party with their enormous wealth and influence. In fact, in April, David Koch told Republican donors: "We will support whoever the candidate is, but it should be Scott Walker."

Walker came to national attention by winning elections in Wisconsin three times in four years. He pushed his state to strip union bargaining rights from public workers. He faced a recall election over that and his Democratic and union rivals poured in money and supporters to unseat him. He still won. And that allowed himself to claim, in a state that hasn't voted Republican since 1984, he was a fighter who could take a conservative agenda and make it palatable to the rest of the country.

He won backing from religious conservatives, the Tea Party and even more traditional Republicans who saw the 47-year-old as electable. And with an impressive performance in front of conservatives in Iowa in January, he was quickly installed as the man most likely to succeed.

He concentrated his efforts in Iowa. The plan was to record an impressive victory there in the first nominating contest next February and take that momentum to the other early states.

Trump challenge

But as likable and personable as he was on the campaign trail, he made a number of unforced errors. And his team struggled to deal with the summer whirlwind of the Trump campaign.

He railed against career politicians. Then it was pointed out he had spent 22 years in elected office. He talked about building a wall between the US and Canada - and days later laughed off the idea as ridiculous. And on the issue of babies being born in the US being automatically given citizenship, he took days to clarify his position. And then he approved spending $250m of taxpayer money to keep the Milwaukee Bucks basketball team in the state. And that left people asking if he really was "severely conservative".

His performance in the first Republican debate was unimpressive. He got little time to talk - and when he did he did nothing with it.

He refused to attack Donald Trump initially - hoping his support would fall away and his supporters would fall into line behind him.

But the Trump bubble didn't burst.

And the polls were producing nothing but bad news. From being at the top, he kept falling and falling. His support dropped to just five percent.

The second debate gave him the opportunity to reinvigorate himself, his campaign and his supporters. But he had a bad night. He took an early swing at Trump but he ended with less screen time than anyone else. No one was talking about Walker in anything but negative terms. It was hard to convince anyone his campaign was in a death spiral.

On the morning after the debate, he huddled with his financial backers and his campaign team. He cancelled a number of events elsewhere in the country, setting his sights again on Iowa. But when the latest polls emerged on Sunday - he was recording an asterisk. That meant his support was so small, it couldn't be measured.

And so he stepped out of the race, urging others who are polling poorly to do the same, to clear the field so that people can challenge Trump.

Walker once claimed he was "aggressively normal". Running for president takes a lot out of a person and family and creates exceptional circumstances.

He can return to being normal once more.

Source: Al Jazeera