British political leaders have risen early to pursue undecided voters on the eve of the general election. They are zigzagging the country Wednesday in hopes that one last push will get the wavering to the polls. Opinion polls have consistently shown Prime Minister Boris Johnson’s Conservative Party in the lead. But the size of the margin is seen as narrowing ahead of Thursday’s contest. All of the parties are nervous because voters are tired after years of wrangling over Brexit. And they can’t be sure where loyalties lie. All 650 seats in the House of Commons seats are up for grabs.