Over the past year Scott Walker, Republican governor of the US state of Wisconsin, has worked his way down a checklist of items commonly associated with a run at the US presidency.
He has written a campaign-themed book and visited Iowa, New Hampshire and other pivotal election-year states. He has stumped for candidates nationwide. He even has criticised conservatives who challenge moderate incumbents, pleasing party elders.
With a growing pre-presidential checklist, it is little wonder Walker is beginning to emerge as a top-tier candidate in a potentially crowded field in 2016. But first he must win a tough re-election race against Democratic businesswoman Mary Burke, his only announced opponent.
"Walker is working his way down the presidential to-do list," said Mordecai Lee, a political science professor at the University of Wisconsin in Milwaukee. "He's doing the formula to a 'T'."
He is hardly alone. Besides Chris Christie of New Jersey, other Republican White House aspirants include two US senators, Rand Paul of Kentucky and Marco Rubio of Florida. Others are expected to join in, possibly Ted Cruz, the Texas "tea party" favourite, or another governor, such as Rick Perry, also of Texas. None of them has officially declared their candidacy as yet.
Still, a Walker run would face big hurdles. He is little known outside conservative circles and is seen as lacking charisma. He has not shown an ability to raise the funds needed to compete against Christie or another widely backed opponent.
If Walker made it to the general election, Republican strategists say, Democrats would hammer him on his record, including his backing of a 2011 bill that curtailed collective bargaining rights of public-sector workers and support for a 2013 law requiring women seeking abortions to first have an ultrasound.
Despite those weaknesses, University of Virginia political scientist Larry Sabato has Walker as the top potential 2016 Republican contender in his closely followed Crystal Ball website.
"Walker has a lot to prove, but he looks good on paper," said Crystal Ball managing editor Kyle Kondik. "There are a lot of questions about how he will perform as a national candidate."
None of the conjecture will matter unless Walker first beats Burke in Wisconsin's gubernatorial contest this year. A poll last year showed the candidates in a virtual dead heat, with 47 per cent of respondents favouring Walker and 45 per cent Burke. But Burke may have room to build support, with 70 per cent of those polled stating they do not yet have an opinion about her.
Walker, by contrast, is polarising. Fifty per cent of those polled view him favourably, 47 per cent unfavourably.
Walker is best known nationally for turning back a recall vote in 2012 after his battle with the state employee unions. His surprisingly strong 53 per cent to 46 per cent margin against a well-organised union effort won him followers among conservatives nationwide.
John Binder, an independent voter in central Wisconsin, is no fan of unions but says Walker has been too aggressive.
"We're not used to scorched-earth politics around here," he said. "I'm not sure I want four more years of Walker."