(CNN) As President Donald Trump prepares to once again make a bipartisan appeal in his State of the Union address Tuesday, members of Congress are linking arms on one of his favorite issues: trade.

Yet they're working against the president, seeking to limit his authority to impose tariffs unilaterally on national security grounds, as he did last year on steel and aluminum, sparking a dispute with the European Union and alienating close partners such as Canada and Mexico

Multiple Republican lawmakers are working alongside Democrats to put forward legislation curtailing Trump's existing national security tariff powers. They include Pennsylvania Republican Sen. Pat Toomey, who recently introduced a bill with Virginia Democratic Sen. Mark Warner that would require congressional approval to impose trade restrictions for national security reasons.

"It is not impossible for there to be a very good reason to use trade measures in response to a genuine national security threat," Toomey told reporters after introducing the bill. "However, we have seen this administration use this tool in a way that was never intended."

Even as Trump and some of his closest GOP allies in the House continue to push for the US Reciprocal Trade Act, which would give the president authority to raise tariffs in response to various duties and trade barriers American products face abroad, senators are renewing their efforts to challenge the White House's approach after a bruising year of escalating trade fights, including a painful tit-for-tat trade war with China that cost US farmers and importers while also contributing to economic turmoil in Asia.

Toomey's bill, a revamped version of legislation initially introduced by former Tennessee Republican Sen. Bob Corker — a frequent Trump antagonist before his retirement last year — expands on the legislation by granting the Defense Department, rather than the Department of Commerce, the power to investigate whether different goods threaten national security.

Toomey's bill would also provide a narrow definition of "national security" and would limit the items that can be considered under Section 232 of the Trade Expansion Act to those related to military equipment, energy resources, and critical infrastructure.

Toomey and Warner have nine cosponsors in the Senate, and a bipartisan group of lawmakers have introduced a companion bill in the House, but proponents could find the same uphill climb Corker faced last year. His original legislation never got a full vote in the Senate, though it passed 88-11 as a non-binding, symbolic measure in July

But they're not the only game in town. Ohio Republican Sen. Rob Portman says he plans to reintroduce a more moderate bill with Alabama Democratic Sen. Doug Jones as early as Wednesday that would preserve the president's flexibility under the provision, while still increasing oversight of decisions citing national security concerns.

While Toomey's bill would require Congress to approve any new trade restrictions, Portman — a former U.S. trade representative — would leave wiggle room for the White House by allowing Congress to disapprove of such tariffs only after the fact.

Portman's approach would also put the Defense Department in charge of determining national security threats under Section 232 but would not rescind Trump's steel and aluminum tariffs, a point that could win over more labor-friendly Democrats.

Portman expressed optimism in an interview Monday that the bill could receive a hearing and mark-up in the Senate Finance Committee now that Iowa Republican Chuck Grassley is chair. Grassley hasn't endorsed one bill or another, but in December he pointed to Portman's bill as "a prudent starting point for the discussion we need to have on Section 232 authority in the next Congress."

"It's important to actually accomplish something here, and that will require us to have a proposal that retains the tool and makes it workable, but also narrows it to its original purpose, which was for real national security crises," said Portman.

Republicans for the most part remain hesitant to split with the President, and Democratic leaders may be unwilling to provoke steel interests by passing a bill that would lead to the removal of Trump's current tariffs.

Others argue that Congress delegated such powers to the White House because the President needs to have a degree of autonomy to make key trade decisions.

"With trade policy, we've given the president authority, and just because they don't like what this President does on tariffs — I don't either like the way he's done it — but I like that the President has the power on tariffs," Ohio Democrat Sherrod Brown, who is eying a potential 2020 run , told CNN Monday night. "Because you have to be more agile and nimble than this Congress can be on something like that."

That drew a joke from fellow Democratic Sen. Sheldon Whitehouse of Rhode Island, who was walking with Brown and quipped: "Now that he's going to be president, he's all into presidential power now."