(CNN) Midterm elections -- like the one coming up in 2018 -- are all about turning out base voters. Why? History tells us that only the most stalwart partisans turn out when the presidential race isn't on the ballot. So if your side wants to pick up House and Senate seats in a non-presidential election, you need to find ways to excite its most committed members.

Which is where the Republican tax plan approved by the Senate last week comes in. And the fact that, according to a new CBS poll , lots more people hate the plan than love it.

Just 16% of people in the poll said they "strongly" approved of the GOP tax plan. That number pales in comparison to the 40% who said they "strongly" disapprove of it.

A similar question -- "Which best describes how you would feel if the Republican tax plan was signed into law?" -- produced equally concerning results for Republicans. Just 8% said they would be "excited" by the new tax law while 22% said they would be "angry." (Another 28% said they would be "satisfied" and 31% said they would be "disappointed.")

Dig into the numbers and the direness for Republicans becomes more apparent. While 46% of Republicans strongly approve of the tax plan, 71% of Democrats strongly disapprove.

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