Elon Musk has become the Republican Party's biggest donor for the upcoming US midterm elections. Musk spent more than $275mn to back key races across the country. These donations were made over the past few months as Republicans seek to shore up several struggling Senate and House campaigns this November.

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* Elon Musk spends $275mn to back Republicans in key midterm races

* US federal agents raid home of Trump critic Ilhan Omar

* Bosnia's foreign minister warns of pro-Russian enclave's Washington lobbying

The world's richest man has become the Republican Party's biggest donor.

Trillionaire Tesla chief Elon Musk has spent more than $275mn on key races across the US ahead of November's midterm elections, my FT colleagues reported on Monday.

The donations were made over the past few months, a spokesperson said on Monday, as Republicans seek to shore up several struggling Senate and House campaigns.

On top of donating tens of millions of dollars to his own America PAC, Musk gave $158mn to the Senate Leadership Fund and $20mn to the Congressional Leadership Fund over the summer, the main Super Pacs supporting Republican Senate and House candidates, according to people familiar with the matter.

The enormous sums add to Republicans' already large financial advantage, with the party's committees and President Donald Trump's Maga Inc raising more than $1.1bn combined, compared with Democrats' roughly $600mn as of the end of August, according to federal filings.

Musk's immense contributions come as Trump's record-low polling numbers have cast a shadow over Republican campaigns.

A new nationwide FT-Focaldata poll published over the weekend found that the president is failing to boost his approval ratings ahead of the midterms that will have a decisive impact on the remainder of his presidency.

While Trump's overall approval rating has remained stubbornly low at 34 per cent, 45 per cent of registered voters said the president was making it harder for Republican candidates to win in November, according to the FT poll.

What do you want to know about the midterm elections? Washington bureau chief James Politi will be answering your questions in a special edition of this newsletter ahead of the vote. Email whitehousewatch@ft.com with your question, plus your name and location.

The latest headlines

* US federal agents raided the home of Congresswoman Ilhan Omar, the latest example of the Trump administration launching investigations targeting the president's political enemies.

* Nato's supreme commander has warned Moscow against attacks in Europe, saying Russia's "hybrid" war is unsettling societies but Nato is always ready to strike back.

* As Trump battles to save the Senate, a vote in rural Iowa may determine his fate.

* The US Justice Department is investigating five television networks over whether they violated federal antitrust law by pausing pooled coverage of Trump.

* US officials lobbied European capitals over the weekend, threatening to block arms sales to Kyiv in a bid to pressure Ukraine to stop its deep strikes on Russian energy infrastructure. Meanwhile, Volodymyr Zelenskyy has blamed Russia for breaking a purported "energy ceasefire" announced by Trump.

What we're hearing

Bosnia and Herzegovina's foreign minister has written to senior US officials and members of Congress to voice concern about Republika Srpska's lobbying in Washington, where the Serb-majority enclave has hired several Trump allies.

In letters seen by the FT, Elmedin Konaković said the enclave's hiring of Trump-connected consultants and lobbyists had highlighted broader concerns "regarding the use of Republika Srpska public funds to develop political influence in the US on behalf of political structures closely aligned with Moscow".

The letter comes days after The New York Times reported that Trump's longstanding aides Chris LaCivita and James Blair were paid hundreds of thousands of dollars to provide campaign advice to the enclave ahead of elections earlier this month.

There is no evidence to suggest that Blair and LaCivita lobbied for the entity's independence.

Konaković noted that Bosnia's top court ruled in September that Republika Srpska, a self-governing entity that forms part of Bosnia and Herzegovina, could not use money from its budget to pay overseas lobbyists to push for the entity's independence, a move that many in the region fear could spark war.

You can read the rest of my reporting on the pro-Russia Serb enclave's lobbying efforts here.