Story highlights Traditional players have waited to unveil spending plans

The exact coalitions and budgets remain ill-defined

Washington (CNN) Opponents and supporters of the Republican proposal to replace Obamacare are preparing for a costly advertising war -- even though the exact coalitions and budgets remain ill-defined as of Thursday.

A few outside groups this week announced small advertising buys meant to bolster or defeat the American Health Care Act, the House GOP plan to replace the controversial Obama-era law. Yet traditional players have waited a beat to unveil massive spending plans like those that accumulated in a $150-million television war just in the first six months of the 2009 battle, according to data from CMAG/Kantar Media.

Both hardline conservative groups and Democrats are likely to spend on ads opposing the bill, in addition to the millions they invest in lobbying against it behind closed doors. Likely spenders include the political network funded by allies of Charles and David Koch, along with The Club for Growth, which said Thursday that it was currently "talking about" spending money to oppose the bill, though claiming "nothing specific" is in the works yet.

Priorities USA, the Democratic super PAC that spent north of $100 million to boost Hillary Clinton in the presidential race, on Thursday announced a digital ad campaign, but the funding was only described as in the hundreds of thousands.

A solace to opponents of the bill is that the coalition of big-money supporters is proving equally slow to form.

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