The over-under for 2012 U.S. campaign spending has officially risen to $4 billion.

Some early volleys:

More to come, the Boston Globe reports:

Joe Miller, a former US Senate candidate from Alaska, has been spending his days in his law offices in Fairbanks with an almost singular focus: making sure fellow Republican Mitt Romney does not win his party’s presidential nomination.

Miller, through a little-known group called the Western Representation PAC, is planning a $500,000 ad campaign with a chief goal of dirtying up the national front-runner – in terms that are far more personal and aggressive than Romney’s rivals for the nomination have used.

“Right now [our focus] is making sure that Romney, who’s very clearly a RINO, doesn’t walk away with the nomination,’’ said Miller, using the acronym for Republican In Name Only. “We’re trying to save the country. And with Romney at the helm, it’s not going to get saved. Romney is just going to be a disaster for this country.’’

Actually, $4 billion of campaign spending is more likely to be a disaster for this country.