It's been a rough start to the trading week for the S&P/ASX 200 Index (ASX: XJO) and many ASX 200 shares so far this Monday. At the time of writing, the ASX 200 has slid 0.44% lower so far this session, leaving the index at around 8,473 points. But let's talk about what's happening with BlueScope Steel Ltd (ASX: BSL) shares.

Bluescope shares are defying the market rather enthusiastically to push higher this Monday. The ASX steel stock closed at $21.51 a share last week. But today, those same shares opened at $21.76 and are currently up a healthy 1.84% at $21.91.

So what's going on here that is resulting in Bluescope beating the market by more than .5% today?

Why are Bluescope shares bucking the market to push higher on Monday?

Well, it's hard to know for sure, as there have been no official news or announcements from the company itself this week.

Saying that, we can make a pretty good guess as to what is happening today.

As reported by multiple media outlets, including the Australian Financial Review (AFR), it seems likely that a fresh announcement out of the White House may be responsible for the boost the Bluescope Steel shares are enjoying.

Last week, we extensively covered the barrage of new tariff announcements coming out of the Trump Administration. Today, that barrage continues, with the news that President Donald Trump has revealed a plan to impose a blanket 25% tariff on all steel and aluminium imports coming into the United States.

If you weren't aware, a tariff is a tax that countries can impose on imports. It raises the price of importing the goods against which it is levied.

Although tariffs have been in decline for decades, Trump has shown enthusiasm for the controversial trade policy. He has stated that he hopes new tariffs will raise revenue for the US government and boost the domestic manufacturing sector.

At this point, despite our country's close relationship with the US, there has been no indication that Australia will be exempt from this fresh tariff on steel and aluminium. However, Australia's Prime Minister Anthony Albanese has just flagged he is making a case for an exemption, according to ABC News.

In the meantime, why would shares of Bluescope, an ASX-based steel stock, be rising on news of potential tariffs?

Benefitting from Trump's tariffs

Well, Bluescope already has extensive domestic steel operations across North America, including in the United States. This means that a big chunk of Bluescope's business will be insulated from any effects of these new tariffs, and may even benefit.

A 25% American steel tariff will arguably raise global steel prices, and American prices even more. If that is the case, Bluescope stands as a major potential beneficiary of this policy, if it does indeed come into effect. This may be what is lifting Bluescope shares on the market today, despite the broader slump of the ASX 200.

Despite today's lift, Bluescope shares have had a rough 12 months. As it currently stands, the Bluescope share price is sitting on a 0.27% loss since this time last year.