When House Speaker John Boehner (R-Ohio) said after the 2012 election that "ObamaCare is the law of the land," he was more stating the facts than waving a white flag. Republicans haven't entirely given up on neutering, or at least undermining, President Obama's signature domestic achievement, but the Patient Protection and Affordable Care Act has survived several legislative attempts at repeal, a harrowing Supreme Court challenge, and now a presidential election that promised critics their last best chance of killing ObamaCare before it takes full effect in 2014. Still, a lot of the nuts and bolts of the law are still loose (or still in their packaging), making 2013 a very big year for the health-care overhaul. Here's a chronological rundown of what benefits and rules kick in over the next year, what has yet to be finalized, and what the GOP is doing to keep up the fight:

What has already taken effect
As Obama noted repeatedly in the presidential campaign, ObamaCare already allows parents to keep their children on their health insurance plans until age 26, prevents children from being denied coverage due to pre-existing conditions, offers some preventative services at no out-of-pocket cost, and prohibits insurers from setting lifetime limits on benefits. On Nov. 20, the Department of Health and Human Services (HHS) published a whole ream of (largely technical) rules guiding how ObamaCare will be implemented.

December 14, 2012
This is the HHS deadline for states to decide whether they will set up their own health insurance exchanges, partner with the federal government, or let the feds set one up for them. "Basically, these will be health insurance stores," says Peter Grier at The Christian Science Monitor, "markets intended to provide a more organized and competitive way for people to buy a product that's often complicated and confusing." Eligible shoppers will include workers whose employers don't provide affordable health care, the self-employed, and early (pre-Medicare-age) retirees.

As of Nov. 29, 18 states had said they would set up their own exchanges, six had signed on for state-federal partnerships, 17 had said they would leave the work to the federal government, and 10 were still undecided. Massachusetts and Utah already have exchanges, although Utah's is "relatively bare-bones" and only serves employers, not individuals, says Sarah Kliff at The Washington Post.

This is one of the major ways Republicans hope to hobble ObamaCare. Setting up the exchanges will be a huge undertaking for the states, and the federal government will have an even harder time setting up 17 to 30 different systems for opt-out states. If the Obama team can't create those exchanges, ObamaCare will lose its conduit for providing insurance to millions of Americans. It would serve Democrats right, says The Wall Street Journal in an editorial. There's no way HHS can pull off the exchanges in a year, and "when it turns out that ObamaCare's costs are underestimated and its benefits exaggerated," why should GOP governors who opposed it be left holding the bag?

January 1, 2013
Regardless of what happens with the "fiscal cliff," a few ObamaCare-specific taxes will kick in at the New Year. For people earning more than $200,000 a year (for couples, $250,000), the Medicare Part A (hospital coverage) payroll tax will go up less than 1 percent, to 2.35 percent of wages. Medical device makers face a new 2.3 percent tax, although the IRS has not yet defined what counts as a taxable "medical device."

July 1, 2013
This is the scheduled date for a group of new Consumer Operated and Oriented Plan (CO-OP) nonprofit, member-run health insurance companies to open their doors for business.

October 2013
At this point, the states' health insurance exchanges are supposed to go live, letting residents browse through the approved options and sign up for plans. As envisioned, shopping for health insurance should be as easy as shopping for plane tickets or rental cars online. Of course, "buying health insurance is a lot more difficult than purchasing a plane ticket on Expedia," says The Washington Post's Kliff. So this is also the informal deadline for "setting up large-scale customer support operations" at the state and/or federal level.

Late 2013
In the GOP's other big shot at striking a blow against ObamaCare, the Supreme Court recently opened the door to a second high-court challenge to the law. In this case, the challenge involves the employer mandate — companies with 50 or more employees will have to provide health coverage or pay a $2,000 fine for every worker past No. 30 — and the requirement that all non-church employers provide free contraception. If a lower court makes its ruling by spring 2013, as expected, says Kilff, "that could lay the foundation for a repeat performance in front of the Supreme Court late next year — just before the major parts of the health-care law are expected to kick into gear."

January 1, 2014
The major parts of the law take effect, including the individual mandate and the employer mandate, and the ban on insurers excluding people based on pre-existing medical conditions. This is also when Medicaid coverage expands to everyone in participating states who earns up to 133 percent of the federal poverty level. Under the individual mandate, everyone will be required to have health insurance, with federal subsidies for everyone earning up to 400 percent of the federal poverty level (currently $11,170 for individuals, $23,050 for a family of four).

Find out how ObamaCare affects you, or watch this video primer from the Kaiser Family Foundation:

Sources: Christian Science Monitor, Health Affairs, Kaiser Family Foundation (2), The Wall Street Journal, The Washington Post (2,3,4)