Since Oct 23, several packages with suspected explosive devices were sent to some people in several places in the United States. According to US media reports, all those people have been frequently maligned by right-wing critics.

Among those targeted are former US president Barack Obama, former secretary of state and presidential candidate Hillary Clinton, former US vice-president Joe Biden, former attorney general Eric Holder, former CIA director John Brennan, prominent Democratic Party donor George Soros, and California representative Maxine Waters, an outspoken critic of US President Donald Trump. A similar package was also delivered to the New York City office of CNN.

Fortunately, none of the packages detonated. And US federal authorities have nabbed Cesar Sayoc, 56, of Aventura, Florida, who has a criminal history and is a strong supporter of Trump. Sayoc has been indicted for sending at least 13 mail bombs to prominent Democrats, capping a nationwide search in a case that has spread fear before the Nov 6 midterm elections, which is unprecedented in US history. Several politicians described the mail bombs as an act of terrorism aimed at trying to silence dissent using violence.

The package bombs have heightened what already was a contentious midterm electoral campaign in which Trump's Republican Party is trying to win a majority in the Senate and House of Representatives.

The "threat" campaign against the Democratic Party and its supporters is an extreme act, premeditated and politically motivated. The bomb threat seems more like a desperate offensive by the extremist elements among the conservatives against the liberal camp that now holds certain advantages.

However, the bomb threat also reflects the anger among some right-wing activists who blame the Democrats for the current woes in the US. For example, the targeting of Soros reflects the resentment among the middle and lower classes toward the small group of rich people and the widening rich-poor gap despite the US' economic recovery.

That CNN too has been targeted indicates that ordinary US people believe mainstream media outlets speak only for a handful of political and economic elites while turning a deaf ear to the voice of the grassroots people.

Such a direct threat to the Democratic camp is most likely related to the perpetrators' belief that voter turnout would be a deciding factor in the midterm elections. The Democrats have adopted a series of tactics, including strengthening the "political identity" awareness of voters in order to convert their advantage in the midterm polls into actual votes, by mobilizing key groups such as minorities to vote.

Besides, Trump has used tweets to urge his supporters to vote in large numbers, which may help lead passive voters to the ballot box, but would also result in excessive mobilization and brainwashing of active voters, which is not good for a democracy. Interestingly, after the package bomb scare, Trump advocated a thorough investigation into the incident and severe punishment of the perpetrators, so as to guarantee the safety of the American people.

Trump and his team might not be involved in the package bomb incident, but the extreme development in the run-up to the midterm elections is more or less related to Trump's constant advocacy of "nativist" ideas and his actions that have exacerbated political and social rifts since his 2015 presidential campaign.

The fact is, both the Democrats and Republicans have mobilized available resources to gain an upper hand in election campaigns, because getting maximum votes has been their overwhelming goal.

The package bomb threat before the midterm elections is expected to strengthen the "political identity" of the voters of both the political parties and increase the voter turnout. But such a threat will also likely scare off independent voters who care only about their own problems and are not too enthusiastic to vote because neither party's victory will help solve their problems.

The author is an associate professor of international relations at Renmin University of China. The article was first published in Beijing News.