The shooting death Monday of Biddeford resident Johan Sebastián Durán Guerrero by a federal agent is bound to transform the campaign to unseat Sen. Susan Collins. Indeed, it already has.

The focus has shifted to our deeply unpopular president, Donald Trump, and Sen. Collins’ support of Trump’s agenda. For months, the focus of Maine’s Senate race was the character and charisma of Graham Platner, an unlikely nominee from Democrats tired of the same old, same old. 

No more.

Once Platner’s campaign collapsed, everything seemed to be playing out pretty well for Sen. Collins, the five-term incumbent who is the third most senior Republican in the Senate and chairs the committee that doles out much of the federal money spread around America.

Then Guerrero, a young father from Colombia, went to go to work and wound up as the latest death at the hands of Immigration and Customs Enforcement (ICE), an agency that has brought alarming new levels of lawlessness and disorder to our streets. Guerrero’s partner and his 3-year-old daughter watched him die.

Maine’s Senate election is no longer focused on Democratic bungling or Collins’ ability to funnel cash to Maine projects and charities.

Voters may remember a months-long showdown this year over funding for the Department of Homeland Security, which includes ICE, during which Democrats pressed for more restrictions on and reform of the agency before they would agree to provide more money for its already enhanced operations.

The faceoff ended, with Collins’ support, when the Republicans pushed through a $70 billion measure to fund ICE for three more years — with no new restrictions.

In short, the Republican Party did nothing to hamstring Trump’s favorite goon squad.

I don’t know how Sen. Collins can possibly justify that. Collins had a chance to force reform and chose not to do so.

In the wake of the Biddeford killing, I was struck by something else. Collins said she phoned Markwayne Mullin, who oversees the Department of Homeland Security, and “urged him to cease all non-urgent vehicle stops.” Mullin quickly agreed.

For some, that’s an indication of the power Collins wields. For me, it is an indictment of her unwillingness to use that power unless she absolutely must. Collins didn’t call after the deaths of Renee Good or Alex Pretti in Minnesota, nor at any other time..

She made the call only when her own skin was on the line.

With Trump at the helm, it doesn’t seem to matter anyway. The president raged at the Mullin decision, posting online that “we CANNOT give up one of I.C.E.’s most important and effective Crime Fighting tools, THE TRAFFIC STOP!”

The race for Maine’s Senate seat is about Trump, pure and simple. It always was and that reality is even clearer now.

If you like the president, vote for Sen. Collins. If you want Congress to have any hope of standing up to him and his movement, the person Maine Democrats wind up nominating deserves your vote.