Senate Democrats unanimously opposed President Trump's tax cuts, but several Democrats in red states are increasingly voting to approve key nominations from President Trump with a little more than six months before the election.

Four of them — Heidi Heitkamp, D-N.D., Joe Manchin, D-W.V., Joe Donnelly, D-Ind., and Claire McCaskill, D-Mo. — voted for both Mike Pompeo's nomination to become secretary of state and for Ric Grenell to become the ambassador to Germany after weeks of attacks from Republicans. Heitkamp made her announcement on Pompeo a week before the vote, leading to a slow stream of decisions by her colleagues that helped get the former CIA chief across the finish line.

Some Democrats defend those votes by saying senators are eventually bound to consider what their voters want back home, regardless of what they think about the president. All four of those senators are up for re-election this year.

"These are members who are working hard every day to represent the people of their state, so sometimes they'll vote with the president. Sometimes they'll vote against the president's position," said Sen. Chris Van Hollen, D-Md., chairman of the Democratic Senatorial Campaign Committee.

"They have the finger on the pulse of their states, and I think they know that to do their job they've got to represent the majority of people in the state," Van Hollen said. "That's what they're doing."

But others note it's something these Democrats have to wrestle with.

"It's a challenge," said Sen. Tim Kaine, D-Va. "I think all of us have the sense of presence of how to assemble a team. I cast more yesses than nos, but if I feel like somebody has a significant problems either on the character — or sometimes [with] character you find it's fitness for the particular position — you vote no. I approach it that way. Most of my colleagues do too."

Along with the four members who voted for the two nominations, Sen. Bill Nelson, D-Fla., voted for Pompeo while Sen. Jon Tester, D-Mont., voted for Grenell. Both of them are up for re-election as well.

All told, those six Democrats have mostly voted for Trump's Cabinet nominees. All have voted for at least 15 of the 26 nominees, and Manchin has voted for the most, 22.

Throughout the past two weeks, GOP opponents called almost universally for their respective Democratic incumbent to support Pompeo.

For example, Missouri Attorney General Josh Hawley's campaign released a web ad pushing McCaskill to back the former spymaster. She said Thursday that she supported Pompeo despite "grave reservations." And Gov. Rick Scott, R-Fla., also wondered Wednesday if Nelson would "do the right thing" and vote to confirm Pompeo since it's an election year.

However, some Republicans are questioning whether playing nice with Trump's nominees will get Democrats anyway, since they all voted against Trump's tax cut bill.

"I would argue from a midterm perspective ... that whether they vote for or against Trump nominees in general does not matter. In certain circumstances they might be able to get a headline that says they're with Trump, and that helps," said one GOP strategist.

"[I]t doesn't matter because every single one of them voted against Trump's tax cuts, and that's going to be the No. 1 proving point in the fall for what are you doing to help the economy," the strategist added. "Republicans will be talking about that nonstop between now and the election, and Democrats won't be able to say anything other than they opposed it or explain why they're working to repeal parts of it."