This week, the Senate is debating a constitutional amendment that would give Congress and the states greater authority to restrict spending on political campaigns. If approved, the proposal would overturn not just the Supreme Court's Citizens United ruling, but decades of Supreme Court precedent on political spending, going back to the mid-1970s. Supporters are arguing that such a measure is necessary to help reduce the unprecedented amounts of money being spent on elections, while opponents maintain it would hurt free speech and political participation. Here's what the amendment would specifically do.

1) It would allow limits on campaign fundraising and spending for both candidates and outside groups

SECTION 1. To advance democratic self-government and political equality, and to protect the integrity of government and the electoral process, Congress and the States may regulate and set reasonable limits on the raising and spending of money by candidates and others to influence elections.

Since 1976, when the Supreme Court has considered whether certain restrictions on election spending are constitutional, it has taken two main things into account. On the one hand there's the First Amendment right to freedom of speech — which the Court believes includes the spending of money on elections — and on the other hand there's a governmental interest in preventing corruption or the appearance of corruption.

Republicans argue that this is the first time in US history the Bill of Rights would ever have been altered

The Court has ruled that laws capping how much an individual or group can donate to a particular candidate are acceptable, because they help prevent corruption. However, overall caps on the amount any candidate or corporation spends on elections are unconstitutional, because they muzzle speech without specifically preventing corruption. (The court's narrow definition of "corruption" has consistently been disputed by some justices in the minority.)

So the proposed constitutional amendment specifically says that both Congress and state governments can limit the "raising and spending of money" meant "to influence elections." It lists several rationales for doing so — advancing "democratic self-government," "political equality," and protecting the "integrity" of the political process. However, it only says that "reasonable limits" are acceptable — so if the amendment is ever enacted, there would undoubtedly be court battles over which restrictions are reasonable or unreasonable.

Republicans have argued that this is the first time in US history that the Bill of Rights would ever have been altered. However, the amendment itself doesn't actually strike out any text in the First Amendment, or the Bill of Rights more generally. What it would do is shoot down the current Supreme Court majority's interpretation that the First Amendment prevents caps on election spending. Much of this interpretation was laid out in the 1976 case Buckley v. Valeo, and it was expanded on by several more recent Roberts Court rulings. But the interpretation has always been controversial, even within the Court itself — the recent major campaign finance rulings have all been 5 to 4.

2) It says corporations aren't people when it comes to election spending

SECTION 2. Congress and the States shall have power to implement and enforce this article by appropriate legislation, and may distinguish between natural persons and corporations or other artificial entities created by law, including by prohibiting such entities from spending money to influence elections.

In the Citizens United v. FEC case, the Supreme Court held that the First Amendment allows corporations and other outside groups like unions to spend unlimited amounts directly on elections, rather than channeling their spending only through regulated and restricted PACs. The rationale was that limiting spending of this kind would mean muzzling speech.

The amendment wouldn't reject corporate personhood as a whole

After the ruling, many liberals harshly criticized the idea that corporations should be able to spend money influencing elections just like people do. "If corporations are going to be given the freedoms that people enjoy, they should be subjected to people's obligations and restrictions too," Harold Meyerson wrote. Many conservatives, however, argue that corporations and other entities are merely "groups of people joined together for a common cause," as Yuval Levin put it recently, and that they should therefore be allowed to spend on politics.

The proposed constitutional amendment would not reject corporate personhood as a whole. Though the idea that corporations are people seems intuitively wrong to many progressive activists, my colleague Dylan Matthews has argued that the concept has proved crucial in defending rights like freedom of the press and freedom of association.

Instead, the amendment states that when it comes to "spending money to influence elections" in particular, Congress and the states can treat corporations (and unions) differently than people, and even prohibit them from spending money at all. The amendment's logic would also allow Super PACs to be banned. Note, though, that the amendment would just give Congress the power to pass these restrictions — it wouldn't put them into effect automatically.

3) It states that press freedom will not be restricted

SECTION 3. Nothing in this article shall be construed to grant Congress or the States the power to abridge the freedom of the press.

This is a pretty straightforward attempt to rebut concerns that the amendment would allow restrictions of freedom of the press, as Senator Ted Cruz (R-TX) has recently argued it would. (Cruz said recently that the "abominable" proposed amendment would allow Saturday Night Live-style political satire to be criminalized, Politico's Lucy McCalmont reports.)

Still, it doesn't quite settle everything. Questions about precisely what counts as press speech versus spending to "influence elections" — particularly among the partisan press — would remain if the amendment's enacted.

What's next?

The proposal needs 67 votes to clear the Senate. If it does so, it would have to win two-thirds approval in the House and approval from 38 states. But none of this will happen for the foreseeable future. Failure in the Senate this month is certain, since not a single Republican is yet on board. Even if Senate passage somehow occurred, the proposal is dead on arrival in the GOP-controlled House, not to mention the many Republican controlled state legislatures.

This gets at the biggest problem that's dogged campaign finance reform activists: the issue has become completely polarized by party, with Republicans almost entirely unified in opposition to more restrictions. To pass even a mere law reforming campaign finance, like the 2002 McCain-Feingold law, bipartisanship is necessary. A constitutional amendment is a much bigger lift.

That's why activist Lawrence Lessig, hoping to boost a solitary GOP reformer to the Senate, backed a primary challenger to Scott Brown in New Hampshire's Senate race this year. But the issue clearly didn't resonate enough with the state's primary voters, and Brown won by a wide margin. "We lost. Badly," Lessig wrote afterward. "There's no spinning this." This proposed constitutional amendment will likely get the votes of most or all Democratic senators — but if Republicans remain solidly against reform, it's difficult to see how it will ever go further.