Senators from both parties are telling President Donald Trump not to fire Attorney General Jeff Sessions. Sen. Lindsey Graham (R-SC) told reporters that “if Jeff Sessions is fired there will be holy hell to pay.” Sessions himself says he won't quit, and will only leave if Trump forces him out. Given the depth of Trump’s rage, that may be only a matter of time.

All of which raises the question: Is there anything the Republican-led Congress can do to protect Sessions — and, by extension, the Justice Department special counsel currently probing Trump’s Russia ties?

The short answer, unfortunately, is no. Sessions’s future, and that of Special Counsel Robert Mueller, will effectively be determined by Trump, and Trump alone.

It may seem ironic and unfortunate that a president at the center of so much controversy has the ultimate say in whether the nation’s chief prosecutor — responsible for investigating the president’s own affairs, and those of his family — gets to stay.

And yet the Constitution creates just such a system, giving nearly all power over prosecutions to the president, largely neutering Congress when it comes to law enforcement and forcing the courts to wait until a case comes to them before they can issue any decisions.

Past efforts to create an independent counsel answerable to Congress or the courts are of dubious constitutionality because our founding document vests executive power — including enforcement of the laws — in the president alone. Congressional investigations like the four current probes into Trump’s Russia ties can also make it harder for federal prosecutors to actually bring criminal cases if the lawmakers strike immunity deals with suspects in exchange for their testimony. (Disgraced former National Security Adviser Michael Flynn has been seeking that type of deal, with no success.)

Congress does have a variety of ways it could strike back at Trump for his handling of the Sessions mess, but those could only be used after Sessions or Mueller were fired — not to prevent Trump from doing so in the first place. That's bad news for both Sessions and Mueller, and it's bad news for American democracy.

The Constitution makes it nearly impossible for Congress to restrain Trump

The Constitution creates an uneven playing field when it comes to law enforcement and the day-to-day operations of the federal government. In broad brush strokes, Article I empowers Congress to legislate, appropriate money, and confirm appointees (that last one is just for the Senate). Article II empowers the president to be chief executive and administrator of the government. This includes, importantly for Jeff Sessions, both the power to enforce the laws (the president “shall take care that the laws be faithfully executed”) and to appoint federal officials.

In theory, the president’s near-complete power is balanced by electoral accountability, as well as congressional power to create the laws he enforces and appropriate funds to support his decisions. In practice, the president dominates the field. He and his Cabinet officials control the vast machinery of American government and are responsible for its day-to-day operation. Congress can rarely act (or react) in time to affect the actual conduct of governance.

And even if Congress could act quickly enough, it lacks access to information held by the executive branch, whether that’s classified information or sensitive law enforcement evidence. Consequently, Congress plays a weak hand in its poker game of power with the president, almost always folding its cards.

Sessions’s future, and that of Special Counsel Robert Mueller, will be determined by Trump, and Trump alone

To help better police the executive branch In the wake of the Watergate scandal, Congress passed (and President Jimmy Carter signed) the Ethics in Government of 1978, which created a “special prosecutor” that could investigate crimes at the behest of Congress, not a president who may have conflicts of interest. This statute was used many times to appoint special prosecutors or independent counsel; over time the statute was also amended to limit these prosecutor’s powers and bring them increasingly under the auspices of the Department of Justice for supervision.

In 1988, the Supreme Court upheld the constitutionality of the statute, in part because the attorney general technically retained the power to actually appoint and supervise these prosecutors. Under the Constitution’s separation of powers, only the executive branch can directly enforce the law. Consequently, any arrangement allowing Congress or the courts to appoint prosecutors, or supervise them, would run afoul of the Constitution’s division of labor.

The law was perhaps most famously used during the Clinton administration, when a narrow probe into suspicious real estate dealings in Arkansas snowballed into a massive inquiry taking six years and more than $50 million, led by a series of independent counsels most notably including Kenneth Starr. The Whitewater investigation eventually led to President Bill Clinton’s impeachment, but ultimately “determined that the evidence was insufficient to prove to a jury beyond a reasonable doubt that either (the) president or Mrs. Clinton knowingly participated in any criminal conduct.”

The Starr investigation and others conducted during the Clinton administration were so thoroughly unpopular that Congress declined to renew the independent counsel statute when it expired in 1999. (In a historical irony, Starr penned a Washington Post column Thursday pleading with Trump to stop attacking Sessions and respect the rule of law.)

Alongside the now-expired independent counsel statute, the Justice Department created its own internal authority to appoint a “special counsel” in situations where the president or senior Justice Department officials may have a conflict of interest.

These regulations require the special counsel to be appointed from outside the government, and be “a lawyer with a reputation for integrity and impartial decision-making, and with appropriate experience to ensure both that the investigation will be conducted ably, expeditiously and thoroughly.”

Someone, in other words, very much like former FBI Director Robert Mueller, who Deputy Attorney General Rod Rosenstein appointed to investigate Trump’s Russia ties — as well as any crimes against the integrity of the legal system like obstruction of justice that may come to the attention of Mueller’s team.

Firing Sessions would be Trump’s first step towards firing Bob Mueller

As special counsel, Mueller has the “investigative and prosecutorial functions of any United States Attorney.” He can gather evidence from other agencies (including classified information from the National Security Agency, like intercepted phone calls with Russian diplomats), interview witnesses, and subpoena witnesses or documents as necessary. If warranted, Mueller can recommend charges to a grand jury. However, it’s unclear whether Mueller could make an recommend indictment or impeachment for Trump himself.

Given this constitutional playing field, and the brief history to date of the Russia saga and its characters (including Sessions, Rosenstein, and Mueller), the president and Congress have only a few options in front of them.

For his part, Trump can summarily fire Sessions — a power he used to oust acting Attorney General Sally Yates and FBI Director James Comey. Whether Trump bullies Sessions into eventually resigning or actively fires him is immaterial. The president enjoys unquestioned power to fire an “officer of the United States,” and Congress can’t stop the president from doing so.

Congress could punish Trump for firing Sessions. It can’t ensure he keeps his job.

At best, Congress can engage in legislative brinksmanship, like beginning impeachment proceedings, or take some other legislative action if provoked. But none of these measures would save Sessions or any other senior official from being canned.

It’s much less clear that Trump can summarily fire Mueller, who is protected by Justice Department regulations from being fired without “good cause.” The emerging consensus among legal experts is that Trump could direct Rosenstein or some other senior Justice Department official to create a cause for firing Mueller, or rewrite the special counsel regulations to allow for his firing.

However, it’s also possible (particularly given Trump’s litigation history in the private sector before taking office) that Trump would bluster forward anyway, ordering Mueller’s firing and daring anyone to litigate its propriety after the fact.

Congress can’t save Jeff Sessions — but it can make life miserable for Trump

Congress isn’t totally toothless, though: It can still make new laws, control the purse strings of the federal government, and block Trump’s ability to appoint new federal officials.

In this instance, Congress couldn’t make new laws that would make it a crime to do what Trump and his associates may have done during the campaign; the Constitution forbids such “ex post facto” statutes.

However, Congress could increasingly tighten the screws on Trump and his associates by strengthening federal ethics laws and making them apply, explicitly, to the president and his White House staff. Walter Shaub, the former director of the government’s ethics office, suggests this would help close many of the loopholes Trump is currently exploiting, such as by creating a legal rule on conflicts of interest that would explicitly apply to the president.

Another possibility would be for Congress to bolster the protections for Justice Department employees and their investigations, or amend the criminal statutes regarding obstruction of justice and related matters to more effectively fence off the Justice Department from White House interference going forward. On Thursday, Sen. Graham said he would try to do just that by introducing a bill requiring a federal judge to approve the firing of a special counsel like Mueller who was investigating the president.

Beyond that kind of new law, Congress could also mandate detailed reports from executive agencies on their programs and activities, and haul their leaders before oversight hearings, to make governance more difficult for the Trump team.

All of this would slowly frustrate Trump’s presidency, and make it more difficult for him to pursue his agenda while dealing with so many investigations and oversight matters.

Another big area where Congress could act is by leveraging its control over federal spending to directly affect how Trump uses the Justice Department, and also to control the rest of his agenda. Nothing in government happens without money; indeed, it’s a federal offense to do something in government without an appropriation. If Trump fires Sessions, or uses his replacement to improperly fire Mueller, then Congress could respond by zeroing out parts of the Justice Department budget.

Or, Congress could threaten the funding for more specific presidential priorities, like the construction of a border wall or his much-promoted infrastructure project. The problem is that many of these projects are pretty popular with the general public, so lawmakers — especially those up for reelection in 2018 — may not want to rock the boat.

A third kind of leverage exists in the Senate’s confirmation power, which both Republicans and Democrats have successfully used to extract performance from presidents.

In 1973, Congressional leaders used the confirmation of a new attorney general to extract the appointment of a special prosecutor for Watergate. Similarly, Sen. Charles Grassley on the Senate Judiciary Committee, or other Republican leaders, could threaten to delay or deny confirmation of Trump appointees. Grassley has already taken to Twitter to say his committee would refuse to even hold a confirmation hearing for whoever Trump would nominate if he went ahead and fired Sessions.

Trump might see congressional retaliation as a cost of doing business

The problem here is that Trump has shown little desire to actually fill appointments in the first place, and any more delay could actually affect the performance of government in ways that politically backfire. Nonetheless, the Senate could easily use this power to guide the selection of Sessions’s replacement at the Justice Department, and the choice of any other appointees to law enforcement positions.

No matter what, Congress would surely use its powers here to ensure that future appointees would continue the work of Sessions, Rosenstein, and Mueller. And, if it became clear that Trump really had fired these men in order to quash the inquiries into his administration, then Congress might finally decide to take political action in the form of impeachment.

Finally, Congress could act by creating a new independent counsel statute (cured of its constitutional infirmities) or by super-charging the investigations now being conducted by various congressional committees.

Both Democrats and Republicans still hate the idea of an independent counsel, resenting the ways it operated during the two decades of its life including major investigations like Iran-Contra and Whitewater, and lesser known investigations into myriad government officials for corruption or influence-related allegations. However, Mueller’s termination would likely outweigh this distaste and cause Congress to look for ways it could build new institutions to check and balance the president. Mueller’s termination could push Congress to create a more aggressive and empowered investigation of its own — one that can leverage congressional subpoena power and immunity authority.

To date, congressional inquiries have focused on Russian meddling in the 2016 election or other discrete issues. But if Trump dares Congress to act by firing the attorney general and special counsel, then Congress could (and probably would) respond with a more direct set of inquiries focused on Trump himself.

In concrete terms, Congress could ramp up these inquiries by hiring more professional staff, using subpoena powers to collect more evidence, and scheduling more interviews and public hearings to build a record — and perhaps a public case — against the president.

For now, the status quo persists. Sessions remains, albeit in what Trump himself derisively calls a “beleaguered” state, recused from anything related to the Russia investigation. Rosenstein continues to oversee the Russia and Trump-related inquiries, despite Trump’s animus toward him. Mueller and his dream team continue to make their way through sensitive evidence, piecing together what happened in 2016 and whether the Trump team committed any crimes then or since.

If Trump does nothing but tweet his anger, the prosecutorial triumvirate of Sessions, Rosenstein, and Mueller will continue their work, unaffected by Trump’s rage except to the extent there is more public interest in their efforts. If Trump acts to fire one or all three, their replacements are almost certain to continue their work. The only question will be how heavy a price Congress will force Trump to pay in the aftermath.

Correction: An earlier version of this story said that Sen. Lindsey Graham had warned impeachment proceedings might begin if Sessions was fired. He actually said this could happen if Mueller was dismissed.