There is a maxim in politics that you shouldn’t give your opponent the chance to change the subject. Former President Donald Trump and Republicans in Congress have done that twice already this month.

The first came on illegal immigration when Trump called on GOP lawmakers to sink a bipartisan Senate border security deal.

Instead of being forced to defend the border policy mistakes of the Biden Administration, Democrats were given a lifeline and they hit Republicans for refusing to address the border until at least 2025.

“Our new winning message is pretty simple,” said U.S. Sen. Chris Murphy, D-Conn., “Democrats supported the bipartisan bill to fix the border. Republicans killed it.”

That argument became a late rallying cry in a special U.S. House election easily won by Democrats in New York this week. It was a race that Republicans had tried to make into a referendum on the border. Instead, it gave Democrats a message for November.

“Their party’s leader told them that he’d rather campaign on the problem than solve it,” said U.S. Sen. Bob Casey, D-Pa., who is up for reelection this year.

Whether that’s a winning argument about the border remains to be seen, but don’t underestimate the power of supporting bipartisan solutions. Independents especially like that message – even if most voters don’t practice what they preach.

The second opening came as Trump boasted about how he told European leaders that he wouldn’t protect them from a Russian threat unless they ponied up more money to NATO.

On Capitol Hill, you could see Republicans wince at Trump’s words.

“It has dangerous implications,” U.S. Sen. Mitt Romney, R-Utah, told us. “That is not something I believe he should have said,” added U.S. Sen. Thom Tillis, R-N.C.

It used to be that the GOP was instinctively anti-Kremlin. Not anymore. Opposition to aid for Ukraine has become a staple for many Republicans as Trump has made clear his disdain for NATO.

The explanation for Trump’s deference to Russia remains murky at best, even as he has dragged the Republican Party into uncharted foreign policy waters.

All of that was a hanging curveball for Biden.

“It’s shameful, it’s dangerous, it’s un-American,” the President said of Trump’s NATO remarks.

“Are you going to stand with Ukraine, or are you going to stand with Putin?” Biden said to House Republicans, hours after the Senate voted 70-29 for aid to Ukraine.

In the fight for independent voters, Democrats see bipartisanship as a solid campaign message — whether it’s on border security policies or countering Russia.

Republicans have certainly given them a chance to drive that home.

Jamie Dupree has covered national politics and Congress from Washington, D.C. since the Reagan administration. His column appears weekly in The Atlanta Journal-Constitution. For more, check out his Capitol Hill newsletter at http://jamiedupree.substack.com