<em>the length of one side of a block, especially as a measure of distance.</em>
A line can be measured. Lining up for blocks would mean people form a very long queue, which stretches over the distance of a few blocks.
Answer:
The President in the executive branch can veto a law, but the legislative branch can override that veto with enough votes. The legislative branch has the power to approve Presidential nominations, control the budget, and can impeach the President and remove him or her from office.