President Trump's campaign has poured millions of ad dollars into issues that resonate with his base. Immigration was the driver. Now, it's impeachment.

Why it matters: This is a stark reflection of Trump's fight-like-hell gambit.

The big picture: It's not just Trump — this is a party-wide effort to cash in.

The House and Senate Republican committees are also putting the majority of their digital ad dollars behind impeachment.

In ads targeted to his home state of Kentucky, Senate Majority Leader Mitch McConnell, who's up for re-election next year, is running ads that say impeachment will fail "with me as majority leader."

The other side: Democrats continue to run ads about a wider array of topics, including health care, dark money, the Republican leadership and Trump.

Go deeper: Trump's burn-down-the-House plan