Republican Sen. Ted Cruz (Tex.)  exits the floor of the Senate after speaking for more than 21 hours in opposition to the Affordable Care Act in September 2013. (EPA/JIM LO SCALZO)

Republicans are in a hurry to stop talking about impeachment -- so much so that even Sen. Ted Cruz (R-Tex.), who usually lines up with the most conservative Republicans on pretty much anything, is trying to change the subject.

And a new poll shows precisely why: It's because it's killing the GOP among swing voters.

The McClatchy-Marist College poll shows political moderates oppose the impeachment of Obama 79 percent to 15 percent. That's a stunning margin. And not only that, if the House GOP did initiate impeachment proceedings, moderates say it would turn them off so much that they would be pulled toward the Democrats. By 49-27, moderates say impeachment would make them more likely to vote Democratic than Republican in 2014.

But it's not just impeachment. As we've noted before, the House GOP's lawsuit against Obama's use of executive orders is turning out to be a political loser too. In fact, it's not much more popular than impeachment.

Americans say 58 percent to 34 percent that the GOP should not sue Obama, and moderates agree 67-22. Moderates also say by a 50-25 margin that the lawsuit makes them more likely to back Democrats in 2014.

McClatchy-Marist College poll

What's even worse for Republicans when it comes to both impeachment and the lawsuit is that they don't even have the effect you might think on the GOP base. They do, however, motivate liberals. While just 60 percent of conservatives say impeachment would make them more apt to vote Republican (i.e. more enthusiastic), 74 percent of liberals say it would make them more enthusiastic to cast ballots for Democrats. And on the lawsuit matter, liberals are 9 points more motivated to back Democrats (72 percent) than conservatives are to back Republicans (63 percent).

On both issues, about one in five conservatives say such overreach would make them more likely to back a Democrat.

Neither is a major subplot of the 2014 election just yet, and the impeachment issue in particular is being pushed in large part by Democrats (though many back-bench Republicans and even some national GOP figures have expressed some level of support, keeping the story alive).

The Republican Party's approval rating is at just 22 percent, which is its lowest in three years. In other words, it would prefer that the 2014 election be about Democrats and Obama. Impeachment -- and even the GOP's now-broadly unpopular lawsuit -- risk helping Democrats change the subject.

Of course, the House GOP can make that lawsuit go away in a hurry, by simply dropping it. We wouldn't expect that, but this poll suggests they might wish they had never brought it.