The No Child Left Behind Act has been languishing without an update for nearly a decade. The good news? The chances of finishing a bill and getting it to the president’s desk by the end of this year or early next are better than they ever, ever have been before.

The bad news? It’s far from a slam dunk—there are still a lot of dominoes that need to fall into place.

Here are some things to watch as the bill moves to the floor of the Senate—and as the House of Representatives tries again, after the bill faltered in the face of conservative opposition.

The House will bring up other amendments, almost certainly including the “A-plus” Act, which would allow states to opt-out of federal accountability altogether, as well as provisions aimed at expanding school choice. A-plus isn’t expected to pass, but getting the chance to vote on it could appease conservatives who doomed the last attempt.

A way bigger deal: The chamber is also likely to consider an amendment, introduced by Rep. Matt Salmon, R-Ariz., that would allow parents to opt their children out of standardized testing without it counting against a school for accountability purposes. It’s easy to see how that could secure major bipartisan support, and be a big game changer, policy-wise and politically.

There’s a lot of pressure, particularly on moderate Republicans like Rep. Chris Gibson, R-N.Y., who opposed the bill earlier this year, to support it this time around, if only to help the process go forward.

Big issues to watch in the Senate

• Accountability: The civil rights community doesn’t think the bill, which would keep annual testing but largely put states in the driver’s seat on accountability, goes nearly far enough when it comes to protecting disadvantaged students. Its solution: An amendment expected to be introduced by Sen. Chris Murphy, D-Conn., that’s likely to call for states to take more serious action with the lowest-performing schools and schools with big achievement gaps. (The language is still being worked out.) The Obama administration, which has similar concerns, will likely stand behind the effort. The problem? Sen. Lamar Alexander, R-Tenn., and other Republicans want as much flexibility for states and school districts as possible.
• Data privacy: Sen. David Vitter, R-La., who is running for governor, wants to add his bill, which would place major restrictions on the use of student data, to the legislation. Vitter’s bill goes further than most other data privacy measures and its inclusion could hinder the NCLB’s rewrites political prospects. Alexander is said to be working with Vitter on the issue, while the Senate bill’s other sponsor, Sen. Patty Murray, D-Wash., is cooking up her own data-privacy measure, which would give lawmakers who care about this issue a chance to vote on it.
• Funding formulas: Yes, it’s wonky, but it matters. For years, advocates for rural schools have been complaining that the Title I funding formula—which places a premium on population density—short-changes rural districts. Sen. Richard Burr, R-N.C., whose home state is a big loser in the current system, is working to fix the formula. The problem? Populous states would lose out, including New York and Illinois (the home states of Democratic leaders Sens. Chuck Schumer and Richard Durbin, respectively.)
• Bullying: This seems like a side issue, too, but it could actually steal the show. During committee consideration of the bill, Sens. Al Franken, D-Minn., and Bob Casey, D-Pa., brought up and then withdrew amendments that would strengthen protections for LBGT kids who are bullied in school. That’s a political hot potato for some conservatives. And in the wake of the recent U.S. Supreme Court decision legalizing same-sex marriage, it’s unlikely either side is going to want to back down from the fight. This could even be enough of a big deal to scuttle the bill.
• Sens. Ted Cruz, R-Texas, Mike Lee, R-Utah, and Rand Paul, R-Ky. Okay, it’s not exactly an “issue.” But these three—either separately or together—have been known to throw up big roadblocks on major legislation. And two of them are running for president. Paul, who is a member of the education committee, was largely absent during committee consideration of the bill and voted for it, but that doesn’t mean he won’t return from the campaign trail to steal the spotlight.

Alexander and Murray are aiming to get their bill off the floor by the beginning of next week.

What happens next? Assuming the House is able to pass its bill, and the Senate is able to keep its carefully balanced legislation more-or-less intact, the two sides will go to conference. And getting an agreement on issues like whether the bill should include a new preschool program (a big Democratic priority, included just in the Senate bill) and whether states should be allowed to let Title I dollars for disadvantaged kids follow students to the school of their choice (a big Republican priority, included just in the House bill) won’t be easy.

The likely course: House GOP leaders will have to make their bill even more moderate so that it can get through the Senate and be signed by Obama.

A conference report that closely resembles the Senate legislation could make it through the House, but it will need a lot of Democratic support, likely including a nod from Rep. Bobby Scott, D-Va, the top Democrat on the House education committee. That means leaders will lose conservatives, including some of the folks whose votes will be necessary to passing the bill this week.