How much does it affect how you think about legislation that it was sponsored by YOUR political party? To a shocking extent, according to this article by The Hill.

We presented respondents with two different education plans . . . [H]alf the sample was told A was the Democratic plan and B was the Republican plan, while the other half of our national sample was told A was the Republican plan and B was the Democrats’ approach. The questions dealt with substantive policy on a subject quite important to most Americans — education — and issues that people are familiar with — class size, teacher pay and the like.

Nonetheless, when the specifics in Plan A were presented as the Democratic plan and B as the Republican plan, Democrats preferred A by 75 percent to 17 percent, and Republicans favored B by 13 percent to 78 percent. When the exact same elements of A were presented in the exact same words, but as the Republicans’ plan, and with B as the Democrats’ plan, Democrats preferred B by 80 percent to 12 percent, while Republicans preferred “their party’s plan” by 70 percent to 10 percent. Independents split fairly evenly both times. In short, support for an identical education plan shifted by more than 60 points among partisans, depending on which party was said to back it.

Thus, policy positions were not driving partisanship, but rather partisanship was driving policy positions. Voters took whichever position was ascribed to their party, irrespective of the specific polices that position entailed.