The news that Mitt Romney is going up with television ads in Iowa clears up any doubt that the former Massachusetts governor is making a real play to win the state’s caucuses and, in so doing, virtually ensure that he will be the Republican presidential nominee.

Romney’s campaign — both publicly and privately — sought to downplay the significance of the new ad campaign, insisting that this was always part of a slow-build strategy in a state where polling suggests the race is totally wide open.

“Mitt Romney has always said that he would campaign and compete in Iowa,” said campaign spokeswoman Andrea Saul. “Going on television is just another tool in getting Mitt Romney’s message out that Barack Obama has failed as a president, and that [Romney] is the best choice to grow the economy, cut spending and create jobs.”

True enough. Romney has visited the state, particularly in the last few months as the field has remained in deep flux, and has kept a remnant of the political team he built there in place — led by veteran Iowa strategist Dave Kochel.

But, Romney has also taken a pass on a number of Iowa political events — most notably the Ames Straw Poll over the summer — and has been reluctant to make a clear declaration of his intentions to be, to borrow a phrase, in it to win it.

And so, while they seek to minimize the import of Romney’s decision to advertise in Iowa, his senior strategy team knows that by spending precious money on what will almost certainly be a month-long television blitz in the state, they are raising the stakes for their candidate in the state.

Raising the stakes, of course, can be a good thing or a bad thing.

If Romney was to win Iowa — a real possibility — it would almost certainly end the race. Romney is a strong frontrunner in New Hampshire at the moment and would only become more so if he won the first-in-the-nation caucuses.

(Remember that Massachusetts Sen. John Kerry was a weak frontrunner — at best — for the Democratic presidential nomination in 2004 but after back-to-back wins in Iowa and New Hampshire the race was effectively over.)

The flipside is also true, of course. By spending real money in Iowa, Romney makes losing in the state far more meaningful.

When Sen. John McCain (Ariz.) placed fourth in the 2008 Iowa caucuses, it was shrugged off as meaningless because McCain had been clear that he was skipping the state entirely. (McCain went on to win New Hampshire and the GOP nomination.)

Romney now doesn’t have that luxury. Losing to former House Speaker Newt Gingrich — the current flavor of the month in the Republican race — in Iowa would now be a genuine blow to Romney (and boon to Gingrich) and could have implications in New Hampshire and beyond.

(It’s worth noting that Romney might always have been hurt by losing Iowa — ads or not — since it was clear that he wasn’t taking a total pass on the state ala McCain in ‘08.)

Iowa will now tell the Republican political world whether the party’s nomination fight is going to be short fight or a long slog. A Romney victory means the race is virtually over. A Romney loss sets up the possibility of a protracted delegate fight between Romney and Gingrich.

Either way, Iowa is back — in a major way — in the GOP race.