• There's a renewed sense of excitement among European officials as U.S. Vice President Kamala Harris becomes the front-runner for the Democratic nomination.
• The U.S. election just '"got way more interesting," a senior EU diplomat told CNBC on Monday.
• But despite the feeling that Harris has a better chance against Trump than Joe Biden, preparations for a potential victory by former President Donald Trump continue in Europe.

There's a renewed sense of excitement among European officials as U.S. Vice President Kamala Harris becomes the front-runner for the Democratic nomination ahead of the all-important election this fall.

The U.S. election just "got way more interesting," a senior EU diplomat, who did not want to be named due to the political sensitivity of the topic, told CNBC on Monday.

"[President Joe] Biden is a great man, with an impressive life behind him, but he is not the future," added an EU official, who also asked to remain anonymous. They also dismissed 78-year-old former President Donald Trump, adding that "the U.S. needs younger leaders."

Many in the European Union recall dealing with Trump and his team between 2017 and 2021 when he was president of the United States. At the time, trans-Atlantic ties slid to historic lows and the two sides clashed over trade, defense and technology — to name just a few points of tension.

As a result, EU institutions welcomed the arrival of Biden to the White House, describing it as a new chapter in the EU-U.S. relationship. Biden's style and policy priorities were a lot more aligned with those in Brussels, including how to deal with the Covid-19 pandemic, climate change and the need to support Ukraine.

However, for at least a year now, EU officials have been preparing for the possibility of a return of Trump to the White House. If he wins the election, they're expecting a deeper "America First" policy, which will likely mean less financial support for Ukraine and possibly tariffs on some European goods.

Speaking last week, Ursula von der Leyen, president of the European Commission, the executive arm of the EU, said that over the next five years, "our first priority will be prosperity and competitiveness."

"Those who are not competitive will be dependent. The race is on and I want Europe to switch gear. And this starts with making business easier and faster," she said.

Trump raised concerns about a potential trade war last week when he said in an interview with Bloomberg Businessweek that he wants to introduce a 10% across-the-board import duty on goods from other countries.

'There are, obviously, doubts'

Despite the feeling that Harris has a better chance against Trump than Biden — who dropped out of the race over the weekend — preparations for a potential Trump victory continue in Europe.

Asked whether he felt hopeful about Harris' prospects, the senior diplomat who spoke to CNBC said it was, "hard to tell, it really depends on how she fills the shoes."

"There are, obviously, doubts, but she has a very different profile compared to Trump, which is good," they added.

Views on the U.S. election are not homogenous in Europe, however, with Hungary's prime minister, Viktor Orban, a vocal supporter of Trump.

One thing, however, is clear: Europe has learned to be pragmatic about working with the U.S.

"We don't discriminate between two candidates," Radosław Sikorski, Poland's foreign affairs minister, said Monday.

"I have met Kamala Harris, her people, but I also meet with the associates of Donald Trump, and in my meeting with a representative of the [European] commission, I advised that we should keep up the dialog with both sides," he said in Brussels.