Rep. Mike Kelly, R-Penn., is mulling a bid to unseat Democratic Sen. Bob Casey in the 2018 elections.

"The people of our Commonwealth deserve two active legislators who will energetically represent commonsense Pennsylvania values in Congress's upper chamber," Kelly said in a Friday statement. "I will be giving this race serious consideration in the months ahead and will make a final decision later this summer."

Such a campaign would pit a Republican who has embraced President Trump against an unobtrusive Democrat who touted the most aggressive liberal attacks on the president in a traditionally blue state that Trump carried in 2016. Kelly would have to first win the Republican nomination in a primary field that has yet to take shape.

Rep. Lou Barletta, R-Pa., another early supporter of Trump, is also considering a run.

Kelly is likely to run as a supporter of Trump's policies, as he has been urging congressional colleagues to get on board with the new president in the course of their legislative work. "Congress needs to do a better job in understanding the reason Donald Trump is our president," Kelly said in a recent Washington Examiner interview. "My request of my colleagues is, all the time, you keep pushing back against him. Why?"

Casey, for his part, has acclimated to the liberal atmosphere of opposition to Trump. He voted to filibuster Supreme Court Justice Neil Gorsuch's nomination, one of the first senators to announce his plan to do so following Gorsuch's confirmation hearing. More recently, he compared Trump to Richard Nixon after the firing of FBI Director James Comey.

"We're in a period of time where we've never been before," Casey told the New York Times. "I've been fighting these battles for years."

It's a break from the traditional Casey political brand, which dates back to his father's tenure as governor of Pennsylvania from 1987-1994. The younger Casey was first elected as an anti-abortion, pro-gun senator in 2006. "You can say that Bob Casey is doing this at some political risk to himself," said former Pennsylvania Gov. Ed Rendell, a longtime ally of Bill and Hillary Clinton. "He always was a Democrat who ran well with moderates and even some reasonable conservatives. Is he throwing that away by being so vocal and emphatic on these issues? Well, maybe so."

Kelly hopes that's the case. "Senator Casey's far-left pandering in Washington along with his paper-thin record of accomplishments during his long career in government have made him a disappointing representative of Pennsylvania," he said.